It's too early to speculate, but I was reading the October solicitations, and Amazing Spider-Man #672 stated that big changes were on the way. Plus, in Venom #8, it stated that, "Flash Thompson suffered a terrible loss". This all comes back to Amazing Spider-Man #670, where in the summary it states,"a long time member of the Spidey cast has to make the ultimate sacrifice..."
 
October solicitations at here.

Could it be Betty Brant? I'm going to say no, just because of the recent issue of Spider-Man. Plus, the Venom #8 summary could just mean that Betty broke up with Flash. But what do you guys think?