As stated by others, the quality is 720p so it will be the same whether you have an HD TV or a monitor. The audio is connected to your speakers, so depends on their quality.
I have really nice PC speakers so the audio works great now and the games are in full 720p HD.
If it wasn't for the fact that the PS3 doesn't have this feature, I would have delayed getting an HD TV a while, but since it doesn't I am getting a new HD TV some time this week hopefully.
It is bigger than my monitor so I expect to use it for all 3 consoles, unless I got a friend over or something, then we can each play different consoles at the same time cause I can have my monitor as a back up.
I've stopped playing most PS3 games lately just cause I don't want to till I get an HD TV and get to play it on that.
Edit: Other features that I love about the 360:
I'm also a big fan of the controller, except the D Pad.
The ability to change the faceplate easily or even mod the whole 360 case is great. I have a special Blue Dragon faceplate I imported from Japan and I love it. Really makes the 360 stand out more.
Thanks to Blacksaber for the sig!
