Using a HDTV as a monitor

I currently have a Samsung SyncMaster 204B which I am using at 1024x768 resolution. When I turn the monitor on, such as at the beginning of the day or after using power saver, depending on how long it's been off, it's very slow to warm up. The screen stays dark for longer than it should, and then it begins lighting up, very dimly at first and gradually growing brighter. It also flickers a lot when doing this. Eventually it gets to full brightness and the flickering goes away. Is this a sign that the monitor is on its last legs and needs to be replaced? I've had it a little over 3 years and it gets used a lot each day.

Now for my second question. Assuming that I need a new monitor, I have been wondering about using a LCD TV with HD as a monitor. The significant thing here is that I have low vision problems and need the best quality "picture" I can get. So my thought is to get one of these TVs with 1080 resolution and HDMI input, then replace my graphics card with one that has HDMI output.

Would this be a significant improvement in picture quality vs a standard monitor? I don't mind investing the extra $ in this setup if it will provide me some relief from my vision problems. Or would I be better off with a standard monitor? If so, any recommendations on what kind of setup I would need to maximize resolution/picture quality?

Obviously I'm no expert when it comes to these things, so any suggestions or thoughts about how to get the best picture quality will be greatly appreciated. As well as pointing out any pitfalls I might encounter with this. Thank you!