This is the first boxing game I've played since the Punchout! NES/SNES games, and I'm hooked!
A friend of mine had Fight Night Round 2 for GameCube, and it was surprisingly fun (it even included a full emulation of SNES's "Super Punch-Out!!"). He got it for dirt cheap at GameStop to play for the week he was 'down-and-out' from being sick. Later that week, I saw Round 3 in the store for only $39, and bought it based off of how fun Round 2 was (and I really only watched him play it - I never touched a Fight Night game until I purchased Round 3).
The 'total punch control' controller layout (controller config. 1) will take a few matches to get used to if you've never played FN before; but once you do the game's an ABSOLUTE BLAST TO PLAY!
Career mode is highly addictive. Playing a buddy head to head is also a blast; during heated matches we found ourselves literally laughing out loud (something we really never do during a heated SFIII match). And if you have a 5.1 setup, switch the sound mode in the options menu to 'surround' and crank it up: the slo-mo replays of those devastating blows is not only awesome, it's pretty gross (and rewarding in surround sound).
The graphics are about as good as you can get on the PS2 (Round 2 on GameCube looks slightly better, at least as 'smoothness' goes) but with all of the in-store demos of the game on XBox 360 ... that comparison isn't even fair (the 360 version's graphics are jaw-dropping). Still, on the PS2, everything is top-notch and this game is well worth your $39.99!
I'd highly recommend it!