Unlike my other impressions this one is more big picture than info-dump of panel contents... bottom line up front first: 
 
This could be the start of a DCAU-2 to rival the Timmverse.
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DC has always been breaking ground with shared character universes and particularly in the animated realm from the original Super Friends, to Timm's epic DCAU, to crossover of Superman and the Legion, to the many crossovers in The Batman and Batman Brave and The Bold... Young Justice looks to be the most exciting and comprehensive adaptation of the entire DCU ever. 
 
Only half the scripts are done and 150 DCU characters have scripted appearances (not just cameo-easter eggs) already.  DC is giving this universe its own Earth... number 16... and supporting it with an on-going interwoven in-show-continuity comic book written by the creators or those close to the process.  There are no embargoes (4 characters were, temporarily off the table but all such restrictions have been since removed), top talent is on the show (Vietti - Batman: Under the Red Hood; Weisman - Gargoyles; Nolan North, etc), and Johns liked it so much he lifted and adapted their Aqualad for his use in Brightest Day.
 
I'm excited because many of the best animated shows ever had a limiting aspect- Avatar The Last Airbender was a terminal story after which you couldn't really keep stretching out the tale while maintaining the integrity of the story.  Gargoyles was always viewed as an expensive experiment and isolated oddity by Disney.  Even Bruce Timm's Batman was limited in scope by its character, embargoes, and not truly given free reign until Unlimited at which point they were running out of time / episodes to tell their stories.  Other comic book shows find themselves shuffled around Saturday morning schedules into syndicated oblivion (or similarly limited by their subject matter- X-Men never showing up on Spidey, the Teen Titans never crossing over with the League, etc).
 
Young Justice, right out of the gate, has DC's full support, a supportive network (CN) with a prime time slot, and characters who are compelling in and of themselves but with rich connections to DCU icons, no limits on using them, creative freedom in adapting the source material as they will for their unique Earth-16, and a universe with unlimited storytelling potential.  Weisman is no slouch and to hear he's taking inspiration from Joss Whedon is
 
Yeah, I'm a little hyped... but this could be the next big DCAU (call Timmverse DCAU-1 and Weismanverse DCAU-2) which at launch already has a 16-person Justice League, a rich history including the Golden Age (panel confirmed: we will see Jay Garrick, yes!) and the sidekick mentor relationships, and a huge cast of characters to fall back on (again ONE HUNDRED FIFTY in the first 17 episodes). 
 
The show is almost trying too hard too be cool, but given its execution I can't fault it.  This take on the DCU will a modern, grounded, realistic-ish take with no prevailing technology beyond holograms (of course, heroes and villains will have advanced tech but that's not "prevailing").  Consider all the little details going into the rendering of Wally West... his goggles allow him to view the full spectrum- night and heat vision- his padded armor allows him to use his momentum as a weapon- like a cannonball.  He's differentiated from The Flash in that he's yet to master stopping on a dime, that acceleration and deceleration acts as a limitation / weakness but also means Wally uses his powers in a more visually interesting Parkour type fashion.  In terms of characterization, as one of the older and outgoing members he's more likely to be romantically entangled and he's the only one on the team to whom Robin has entrusted his secret identity.  That's for a character who just "runs fast, tells joke" in just about every other rendering. 
 
The team is cast as a covert-ops team getting their missions from Batman... again, trying quite hard to be cool (and before you protest that they're not the Outsiders, I have but one response to you: "EARTH-16").  They've gone so far as to calculate the relative aging of a martian to earthlings, made the Guardian a cool obstacle, and have dedicated an entire episode to explaining why Aqualad is the leader even though Robin is the most experienced hero.  They care about rationality.  The large overarching theme of the series is secrets... and they're definitely taking a page out of how Identity Crisis stepped up the rationality on the DCU as whole.  With the League formed, now the villains are organizing as well (again, shades of the post-Identity Crisis rationality). 
 
You may have seen cam footage of the 5 minute clip we were shown in the panel.  A few things to note about the clip: 1. It looks way better in person; 2. It will look better (there is still some post and editing to be done but they wanted to provide us with a tease); 3. That was the second time they showed it at the end of the presentation (if you're wondering why the audience was so sedate)... the first time we were hollering and applauding at just about every frame, the second time we enjoyed it in rapt silence). 
 
The show has a 1-hour special premier in November and then starts regularly in January 2011.

  Seems like a long wait for me to decide whether I will watch it in January or completely disregard it.

I am excited 

Assuming you watch the marquee CN shows at all, it'll be difficult to "disregard" as Young Justice is being seen as CN's next anchor to replace Clone Wars. 
 
For those upset about the draft- again Earth-16- but creatively, the panel addressed the issue as history being particularly important to the present generation of sidekicks... that is, there's no real way to do justice to Tim Drake if you haven't first discussed Dick Grayson.  Moreover this is their universe and a reboot at that (Superman's been doing his thing ten years max, restarting the wave of superheroes since the Golden Age heroes, Dick the "vet" of the group has only been doing his sidekick thing 4-5 years).  By starting with a young universe they give cartoon watchers a fair shot of getting into relevant continuity / mythos rather than being thrown into a show that is nothing but winks and references to things they have no familiarity with (part of the downfall of Brave & The Bold... older fans get all the nods but kids have zero background on why they should care about Firestorm, Guy Gardner, etc). 
 
Plus, this is a rational / growing universe... we already know that Speedy is going to evolve into Arsenal over the course of the show.  If the series goes as long as the Timmverse you very well could see the evolution of Dick to Nightwing, the ascension of Tim Drake, the rise of Impulse, etc.  The idea of a time-skip is not at all unfamiliar to animation (it's a staple in anime, it happened in CN's Ben10, and is a way for the show to refresh and avoid financing / syndication issues).  DC is storytelling mythology not religion canon... adaptation is inevitable and rather a part of the art.

Superboy!!!

The Aqualad character is very cool.  First, his voice actor is Cyborg from Teen Titans, but he's so talented and has such range that he was able to do something completely different and unique with his voice that you'd never know it unless someone told you.  It carries an authority, deep calm, and maturity fitting of a team leader and it has an exotic quality fitting of someone from somewhere foreign or alien (here, under the sea). 
 
In terms of character design, he has a instantly distinguishable silhouette given his water weapons and fins, the dark red is more acceptable than the bright orange of his mentor.  It's cool he prevents Young Justice from being Team Caucasian and that it is done organically by making him the son of Aquaman's nemesis Black Manta, which supplies great redemption fodder and revelation drama / father angst. 
 
With respect to power speciation he's got a bit of everything... enhanced physical abilities, advanced Atlantean technology and sorcery, as well as a bit of a mutant-type thing going on.  His eel tattoos on his arms (sorcery?) grant him electrical powers and command over water and give a nice visual cue by lighting up in the process.  Finally, his weapons are sweet... powered by his tattoos (meaning no one else can wield them) they project whatever weapon he wants which he can then dual wield into combat... it's like a lightsaber on steroids. 
 
I guarantee this show will make Aqualad fans out of people who thought Aqua-anything was a joke.