Minor quibble: I understand the importance of roles, but to me it's all about the specific class.
I voted for striker, but that's because I absolutely adore my Half-Orc Rageblood Barbarian + Bear Warrior. I have something interesting to do every single round: slow and daze are barely obstacles due to charging with Howling Strike, and bonus attacks flow like water from Rampage and Swift Charge. And look, I got some THP. Plus, I get to growl "ROAR", at least until my fellow players get tired of it and put a bag over my head.
By contrast, although I enjoyed a damage-oriented Fighter that I briefly played, my Swordmage is much more fun in theory than in practice. Her Aegis of Shielding is hard to place (2 square range) and doesn't get triggered very often -- typically only once or twice per combat. In the last big encounter we had, she was almost useless because she had no ranged powers.
I think I would enjoy playing a Wizard, but only if I get a chance to play it my way. I want cool opportunities to use cantrips and rituals, and enough time and gold to play "party armorer" -- to craft magic items to turbo charge the entire party.