Namor - This 12-issue series from the early 2000's is mostly about Namor as a teenager meeting a human girl and a romantic relationship growing between them. It may sound cheesy but it's actually good Namor series since the artwork is really good and the character development is great. Newcomers might not like this series but if you're a newcomer to Namor and want to read this series then go ahead.
New Avengers - This series does feature Namor as a member of the Illuminati and he does steal the show at times even if he acts like a mean person. Jonathan Hickman does a really good job writing him and he ends up playing a huge role towards the end of the series.