If it supports the high resolutions like 1280x1024 or something up there you are set, which I'm assuming 99% of PC monitors do. The only issue your going to have is size, I played on a 17" LCD with VGA cable at 1280x1024 for months and months I just got a Westinghouse 32" LCD HDTV near X-mas for $699 and its like playing on a PC monitor just 32", which is awesome.
In conclusion, the 360 looks really good on PC monitors, especially on a budget.