Getting a widescreen TV

[G-Hawg]

Hello World,
This thursday I am buying a 43" widescreen Digital Flatscreen. HD-Ready.
Last year I built a workstation, and it has a FireGL-Z1.
I am running Windows XP pro. I want to skip on buying a seperate HDTV tuner. I already own a "higher-end" graphics card.
A Large TV is needed because I spent hours in front of the thing programming Actionscript, photoshopping and 3d'ing. Sitting against the computer monitor for hours on end seemed it would be more difficult than sitting in front of a TV for many hours.

I was wondering, does anyone have this setup or something similar??
How can I get a FireGL-z1 to display 16:9 on a TV? Not just movies, but the whole operating system and all.
I do have an ATI tv tuner card, but even still the operating system is running at 1024x768(I think it is?) and has default aspect ratio options. I want to use the DVI connections.
I'm aiming to get it displaying a 1280x720. Is it possible?
Catalyst drivers? No clue what that is.
I would test the darn thing first, but my computer is in Ohio, will be delivered here at the end of May. I am buying the TV thursday, just researching ahead of time to avoid future headaches.
Anyone with info, please help.
Thanx.
GH