Paragon, easily. Unlike the Ranger with their Preps and such, Paragon just run into battle, stop midway and scream at the party without any pants on, which is a nice change of pace from the slower long-cast classes (which use pants). Plus their Primary Attribute is pretty awesome, like a friendly (albeit weaker) Soul Reaping (like a... Voice Reaping! ;D). It's crap early on, but when you start getting the 6-8 people groups, it really shines since your energy rarely drops below 5. (And yet when it does, you just use an adrenaline shout like GFTE! to bring it back up.) It's a fun fast-paced class that has unstripple effects on your allies, endless burning with like 2 skills, good DPS, a great'holy' class (with wings), unlimited energy with enough people, good team support, a wide array of condition attacks, and the only class without pants (the real reason to go it.

) There are times when I feel like I want to add an extra 4 or so skills to my bar, but I can't.
Then again, Rangers get... uh, flamingos. Yeah, flamingos are cool, right?! (Oh, and they get pants... booo.) I maxed my armor on my level 3 Ranger, but now I feel the fool since I wanted their interrupts and decent skills, but might just make a Mesmer instead since I don't feel like grabbing 23 bows to do 4 things.
I don't like pre-battle preps and such when I play (or long casting), which is why I hated the Dervish and the MM Necro. So far Warrior and Paragon have been my favorite classes. ^_^
/Bias