Heroes, Heroes, Heroes - what can I say about Heroes?
Well... it's EPIC.
The first season, obviously, is the most compelling - purely, for me, as it is the original line up of characters, problems, relationships etc. Season two, although (only slightly) not as good as season one, introduces some awesome new superpowers and characters who are intriguing (my only major problem with season two was Kaitlyn - while i was glad that Peter left her in the future, it was kind of unrealistic). Season three was on a similar level to season two for me, very unexpected twists and a weird but entertaining finale.
I've not started season 4 yet, although i think its on like episode 6 or something here in the UK - i have them recorded ;)
Overall, Heroes will not disappoint it has something for everyone: Hiro and Ando provide the comedy, all the characters' personal situations provide the drama, explosions, decapitations, face-offs, and epic season finales provide the drama, Peter & Nathan provide not only tension and drama of their own through their on off brotherly relationship, but also gorgeous eye candy - especially Peter ;) and every characters story, though they all intertwine and have the same starting point, is completely unique. Also, i found that as the seasons progressed so did my opinions on the characters, i found myself falling in and out of a friendship with Bennett and Angela and especially, Nathan in season 2. But that's the beauty of the show - you get to make a connection with these characters and share a common interest... 'save the cheerleader, save the world!' Yatta!