Some questions...

[CruX]

So I'm going to get my 360 some time this week, but I still have a couple of questions...
I'll be playing on a pc monitor, not sure which one yet still need to buy one .
What would be the best to get? A standard 4:3 or 16:10?
If I get a 16:10 none of the VGA resolutions will match... What happens? Do I get black bars or does the image get stretched to fit? Same question for the 4:3 since all games are made for 720p do I get black bars or are they adapted for full 4:3?

Also I have a 5.1 for my pc, a cheap Logitech X-540, it uses 3x3.5mm jacks(no digital input as far as I know) can I connect this to the 360 ?

Any recommendations for a monitor are welcome as well, I can spend about €250 on the monitor.