Just for series that are still running and (as far as you know) uncancelled. And spoiler code any specific plot elements that are less than a year old to avoid any bickering in this thread... 
1. Dexter Morgan - Incredible performance by Michael C. Hall plus the fun of seeing someone who has created his own alternate moral universe, the embodiment of the Mythbuster's motto: I Reject Your Reality and Substitute My Own. That's the spirit!
2. Kara "Starbuck" Thrace - Headcase? Prophet? Sometimes hard to take, but always entertaining. Great performance by Katee Sackhoff.
3. Peter Petrelli - Sure, he's an emo twit and unfortunately subject to dumbed-down writing at times, but he's still a great example of that winning normal-person-gets-superpowers Spider-Man archetype.
4. Sam "C-Buck" Anders - Much more interesting now that his Big Secret is out; my favorite Cylon by far. Who doesn't love a Sexy Tragic Robot(TM)?
5. Ari Gold - How can you not love this complete maniac? A great example of how to make an unappetizing character weirdly charismatic. Jeremy Piven deserves his shelf-ful of Emmys.
6. Sayid Jarrah - Just too cool, a complex, level-headed but still mysterious character who manages to stay grounded amidst insanity.
7. James "Sawyer" Ford - Funny as hell, smarter and crazier than he seems, always entertaining.
8. Matt Parkman - The other great normal-person-gets-superpowers character from Heroes. At this point, I'd watch the show for Peter and Matt alone.
9. Ned - The Pushing Daisies cast is probably the strongest on TV overall - they all belong on Top Ten lists - but Ned is the heart and soul of the show, and the character who most of all keeps me watching.
10. Cameron aka Rivernator aka Cam-bot - We've all seen any number of attempts by actors to portray robots, but Summer Glau ranks right up there with the best. Simultaneously deadly and deadpan funny.
And yes it's true, Gabriel "Sylar" Gray failed to make the list, despite my penchant for characters with nicknames. I'll see how things shape up for him in S3.
1. Dexter Morgan - Incredible performance by Michael C. Hall plus the fun of seeing someone who has created his own alternate moral universe, the embodiment of the Mythbuster's motto: I Reject Your Reality and Substitute My Own. That's the spirit!
2. Kara "Starbuck" Thrace - Headcase? Prophet? Sometimes hard to take, but always entertaining. Great performance by Katee Sackhoff.
3. Peter Petrelli - Sure, he's an emo twit and unfortunately subject to dumbed-down writing at times, but he's still a great example of that winning normal-person-gets-superpowers Spider-Man archetype.
4. Sam "C-Buck" Anders - Much more interesting now that his Big Secret is out; my favorite Cylon by far. Who doesn't love a Sexy Tragic Robot(TM)?
5. Ari Gold - How can you not love this complete maniac? A great example of how to make an unappetizing character weirdly charismatic. Jeremy Piven deserves his shelf-ful of Emmys.
6. Sayid Jarrah - Just too cool, a complex, level-headed but still mysterious character who manages to stay grounded amidst insanity.
7. James "Sawyer" Ford - Funny as hell, smarter and crazier than he seems, always entertaining.
8. Matt Parkman - The other great normal-person-gets-superpowers character from Heroes. At this point, I'd watch the show for Peter and Matt alone.
9. Ned - The Pushing Daisies cast is probably the strongest on TV overall - they all belong on Top Ten lists - but Ned is the heart and soul of the show, and the character who most of all keeps me watching.
10. Cameron aka Rivernator aka Cam-bot - We've all seen any number of attempts by actors to portray robots, but Summer Glau ranks right up there with the best. Simultaneously deadly and deadpan funny.
And yes it's true, Gabriel "Sylar" Gray failed to make the list, despite my penchant for characters with nicknames. I'll see how things shape up for him in S3.
