I have this game on both PC and 360, but I've never tried it because it has no single player. I at least want to try a game out and learn the mechanics of it first before going online.
The best thing Valve did was add an Offline mode to this game. When I first played, I had to jump in and feel stupid for not knowing how to do most anything. It really helps. You can play a tutorial to get used to the controls or play against some bots to get a feel.
They also have a "coaching feature" (which I haven't tried) where a season veteran talks you through the game play and helps you.
TF2 is quite fun but far to many people play it like a regular shooter, TEAM is a key word here. A team of 6 snipers and 3-4 others will not win.. of course those snipers are happy as they stand way back and get 3-4 kills to no deaths while us idots run in as a Heavy or pyro .. or a grunt soilder or demo... TF2 should only assign points (and kills to winning teams).. maybe some TEAMWORK would develop. heheh sorry for rant.. Great GAME! and free rocks..
I must say it does have one downside. STEAM is digital crack.. the daily sales and weekend sales will have you with an empty wallet in no time 
Agreed. A good solution to this is to get yourself a headset mike and not be shy talking to others. I will often make comments when my team is like you described (too many of one class) about how we need Medic/Engineer/Scouts/etc. and not eight spies, few of whom are even cloaking. If my team doesn't listen, I either just have fun with it anyhow or move to another server.
Crap this thread is making me want to get back into it. Such a beautiful game.
Yeah, this thread got me back into it too (though I hardly left - as of this post I have 239 hours into in, more than any other game I ever played). I even put my stats back in my sig in case anyone wants to hit me up on Steam.
Also: saw this interesting little tidbit - TF2 as a side-scroller: