I get asked this from time to time and most people assume they know the answer being that my main character and most well known identity is a mage (FatalLace of Bijou), but that's not really the case anymore.
I really do enjoy playing all 4 classes under the right circumstances. I'm well aware of each classes' strengths, limitations, and challenges so I'm not expecting the unreasonable when I sit down and start playing.
There are some somewhat ironic facets to each character class and my respective style of play that maybe gets some people shaking their heads a bit, but it's how I've learned to best enjoy the game for myself.
Mage (Warlock), currently level 100: I do enjoy playing the mage character, but not as most normal players do. I tend to solo or duo with my fighter husband (IsseyWhiteRain Knight Class) rather than look for full-scale grinding parties, having a cleric around is about as rare as godly Tear's Marsh drops. Reason I enjoy the solo or duo is simply that I get bored easily. AOE soloing is a real challenge and can be equally frustrating and rewarding if done correctly. If I start grinding again, maybe I'll post a video or something, at the moment it would be difficult since I no longer have an active HP/SP extender on that character. I would AOE Phouches solo in AR, duo those same mobs with my hubby, or we would double pull the main boss room in TOS. Those double pulls are really intense and require the mage (and Knight for that matter) to keep focus. A miscast here or being slow to pot there could easily mean the party is overrun. Five person black bear or phouch parties are okay, but I am extremely bored within about 15 minutes even if i'm acting as the main mage. It's just not something that interests me.
Fighter, currently level 90: Although my fighter is a DD build (Str/Dex), I actually play her more like a tank. Honestly, I prefer the sword and shield to the axe although I do carry both weapons with me at all times, although the SP consumption when using the one-hander is pretty significant. I would prefer to play the tank role in a party than solo, so a flip-flop of my role when I play mage. Strange, isn't it? I absolutely LOVE tanking in Dragon's Tomb provided the party I'm with also understand their roles.
Cleric, currently level 90: Clericing can be fun at times, but this is still my least favorite class to play. It can be a frustrating experience when I see my party mates getting into situations that they shouldn't be in and putting the entire party in jeopardy. It's rare that I ever actually die on my cleric, but having the rest of the party get wiped out isn't much fun either. I know I'm definitely most critical of other players when I'm on my cleric just because I can observe a bit more. I watch the other players placements, see what they're targeting and not targeting, etc. I get most critical of self-proclaimed "tanks" that don't watch out for the rest of their party. They think a mock and a devastate is good enough. They don't run out and kick the ranged mobs or even just give them a demoralizing hit to boost their aggression towards himself. Meanwhile, I'm healing the tank and getting pelted by those ranged mobs that he failed to attract. Of course I can, and do, pull those mobs into the rest of the pile by retreating a bit. Pseudo-genius tank then decides to mock them all now that they are in range again. Go figure.
Archer, (Sharpshooter), currently level 101: I absolutely LOVE playing the archer class. Yes, they are limited in PvP, yes they have troubles finding parties, but regardless I enjoy them immensely. But here's the kicker... I hate kiting. This is one of those moments where you're allowed to shake your head in confusion. Don't worry, I get that a lot. I completely see the value in kiting and I do do it, so don't think that I don't. I would rather gather on my mover and then do a stationary AOE on the mobs, but depending on the strength of the mob, that's not always possible. I guess it's a lazier way for an archer to get by. Having decent defense, great evasion definitely helps. Some fellow archers, like R_Z_A, consider me blasphemous for grinding like that, hahaah. I actually like playing in a party as an archer, I wouldn't call it relaxing, but it kind of is. You launch your AOEs over and over while keeping an eye on the surroundings for other mobs that may attack the party. Archers should always target ranged mobs, especially those that heal, as well as smaller regular mobs before adding concentrated damage to the boss. I'm always trying to steal aggro from the fighters and mages just to keep myself entertained.
So what's the verdict? If I had to choose right now, a single class to play, it would be the SharpShooter. Revisit this again in a month though, and I'll probably have changed my mind yet again. =)