Either get a new tv tht has inputs for all your electronics, including your pc, or a monitor tht has inputs for all your electronics.
I have a tv tuner in my pc so i dont need a tv. Im going to college next year and plan on simply buying a samsung 244t. It has plenty of inputs. I also have a homne theatre system with a bunch of inputs and outputs, and a projector for big screen movies and video games. I dont need an actual TV set, i'll use my comp and its monitor.
If your not looking to buy new display sets, get splitters/adaptors for your monitor, and/or the xbox vga cables.
However, i dont see how/why your tv sucks. I lpayed my 360 on an hd set for a long time before upgrading and had barely any problems (only in text heavy games cuz the text is optimized for 720p and higher, even tho most ppl dont actually have hd sets yet.. which is extremely dumb) and even now i only have an ED projector, Its not even hd.