You can get a 40GB non BW compatable PS3 for 300 right now (check ebay). You shouldn't have to pay more then 400 for a 80GB, 60GB or 20GB BW compatable PS3 (again, ebay).
I do second what many people said though, I almost never use BW compatability except once in a long while when something like Persona comes out. It is still better to have it then not though since it does upscale PS3 games (though if your TV is less then 40 inches it won't make a huge difference over a PS2 with component cables at all).
If money is tight you can get a non BC PS3 for under 300 dollars, if money isn't tight go for a search and find a 400 dollar 80GB motorstorm bundle PS3 (its newer if you're concerned about launch PS3s, though my 60GB is from launch and works fine).
PSN ID: ChosenOne feel free to add me
