For me it would be Scout, on both occasions. 22 points with over 8 hours I believe played. My other is the Heavy with 22 points 33 minutes played.

Second is soldier with 19 points without a medic.

I only played Team Fortress while waiting for UT3, so mine's a little short.
My highest kills is Sniper with 15, however my play time is only 25 minutes.
My longets play time is the Heavy Gunner with 6 hours, highest spree however is only 10.

I have like 30 points record on the heavy for some reason, most likely because someone set their server onto that achievement map and i just sat there next to the supply cabinet spamming bullets down the spawn line of the enemy =/

Max Points: 33, Medic
Max Frags: 24, Engineer
Max Damage: 4478, Soldier
Longest Life (with an actual combat class): 12:02, Soldier
Longest Playtime: 56.6 Hours, Soldier

I could probably do better with the soldier if I played on noob servers more often, but I like hanging around on clan servers where all the leet people are. Much better challenge. :P

I don't have the stats right in front of me or nothing, but my favorite class by far is the Sniper, outweighing everything else by about 6-7 hours... and about 11 hours total...

But my best killstreak was 25 kills with an engineer, also 19 with a Spy and 19 with the Sniper...

Although this is one of my favorite games, I don't have online access so I can't play it much, but I used to play it a lot when it first came out and I lived in japan...

18 points with the Spy with 6 backstabs helping.
9 kills with Heavy around 5 of those were Scouts.
Hey lets rush him, don't worry about his Medic.

6:30 hours time spent as Engineer, I tried my best not to play as him.
11 kills with a single sentry (but I died 4 times between them)
(This was for the X-Box version)

I didn't actually have the game that long, I played 25 hours total.

Most kills - heavy with 33 (6,5 hours of playtime)
Most Damage - haevy with 8097 (same round as the one above)
Most points - sniper with 38 (24 kills, 12 headshots, 2 destructions I think)
Longest life - 22:14 with sniper (same round as the one above)
Most health healed - 6278, medic.. of course
Personal Achievements Earned:78 of 94 (83%)

I'm fairly satisfied with my stats as none of it was done by farming (BarbeQueQ was done by asking kindly if someone I dominated could leave for a sec). 85 hour playtime.
Longest: pyro, 20 hours.
http://steamcommunity.com/id/TZer0/stats/TF2

Is there a steam equivalent for TF2 for the 360; something like Bungie.net?

24 as Engineer: 6hours and change

Medic for time and Heavy for points. Fun times.

Heavy, 29 points, all thanks to 2 fort. 26 minutes

Most frags: 62 as heavy
Most points: 75 as heavy
Most playtime: > 14 hours as sniper
Longest life: no idea

Today I smashed my old sniper record of 20 points, got it up to 45! That's now most points, was engineer with 37 (both scores on Dustbowl).

I'm also a sad bastard and have played engineer for >25 hours, and the one below that's on like 10 hours. Though I have been playing since it came out, and really like the engineer on defense.

Aw gawd I play this game so often.

Engineer is my top with 57 points, 47 frags in one life. 59 hours.
Medic is my second with 49 points, not sure how many assists but 14550 healing in one life. 56 hours.
Pyro is my third with 33 hours, 19 points and 16 kills in one life.

I've got engineer wth 25 points
Most played engineer around 8 hours I think?

Its a great game. I always go engi on defence.

I loves me some pyro.

71.2 hours played, best life is 41 points. Highest score is 161:35, but best is 104:19. God bless the pyro update.

brabz:
Is there a steam equivalent for TF2 for the 360; something like Bungie.net?

24 as Engineer: 6hours and change

If I remember right Valve were considering it but MS said "no thanks".

Also (not related to above quote) my most damage is around 12000 with pyro - no I am not an achievement whore, I was good with - and playing - Pyro before the pack was released. Bastard newb pyro's are travelling like the plague and they mostly suck >_>

My top scorer is the Medic with 42 points
Longest used character is the Demo with 43 hours the second being Engineer with 19 hours and the least used being Spy with 2 hours.
Most kills with Demo at 23.
Most Damage 5158 with Demo.
Most healed 13400, as Medic of course and during that I produced 13 Ubers. That was a single special moment for me though as I think my other best is like 3500-ish healing and 3 Ubers...

I have yet to play TF2 admittedly. If I was to, I don't know which class I'd be, because they all look good, cept' the sniper who looks kinda samey, and the spy, who looks quite challenging to master.

Demo for everything, not sure the numbers though.

Don't know my scores, but I'm a pretty good heavy player myself.

Anarchemitis:
I have yet to play TF2 admittedly. If I was to, I don't know which class I'd be, because they all look good, cept' the sniper who looks kinda samey, and the spy, who looks quite challenging to master.

spy is my second most played class, 4th highest in points with like 16 or something. He's pretty fun until someone catches on to your game, the easiest way to go about it is get in the back take out the sniper(s) and make your way back into your own base, rinse, repeat. Also the easiest way to get points with a sniper is to own the faces of clumsy/nooblike engineers. Sapping buildings ftw.

47 points with medic, was doing the 10k heal in one life achievement that time :P