32 players would be great on larger maps. On the maps that shipped with the game, 32 is too many. But I can easily think of maps where you'd want 32 players -- something like Canalzone comes to mind where all five control points can be in contention at any given time. When you have multiple battle locations, it really helps to have lots of players. Right now, 2fort and gravelpit are the only maps where you have two battles occurring at once. 2fort is far too cramped for 32 players, and in gravelpit, the battle almost always shifts quickly to only one place at a time.  But in a map like Canalzone, I can even see 40 players being fun.

I havn't tried other maps but being a semi-regular at a 32player dustbowl server, I can say it actually works very well.
I've seen BLU capture all 3 stages (3rd stage somewhat harder than the first two, but still possible) several times.
another thing I like is BLU is forced to have organized teamwork if they want to win, meaning usually setting up multiple ubers at once and Engineers supporting w/ teleporters.

Aside from that, I played my first instant-respawn server and I HATE IT.
Intended gameplay of TF2 is totally ruined. I'm not here to play deathmatch sorry.

Ok, so I'm getting the Orange Box tomorrow, and I can finally play TF2! My SteamID is adajio , so everyone add me

I added you, I will be playing TF2 tonight, just like practically every night!

The game is overly addicting...it doesn't even tell me my total hours played...i'd have to add up each class' hours hehe.