PC Display question

Sorry if this question has been asked before, but I'm looking to upgrade my PC display to a TV size. I know I have a video card that can handle it, because I tried it with one of my existing TVs and it worked but the resolution sucked.
I was told that the reason it was blurry was because the TV cant handle the PC resolution output unless it is a HDTV.
My question is, assuming this is true, does the TV I buy have to be a HDTV already or just HDTV-ready? What's the max resolution you can get on a TV that you use as a PC display? I'm looking for about 26-30"; if you guys find any that will work and can link me, I'd appreciate it.
Thanks in advance.

The best resolution you can run on an HDTV is 720p. That's 1024x720 non-interlaced (interlacing makes you loose resolution, doh!). So it's even better than 1080i for computer video.

Supported modes for HDTV's are usually advertized.

There are some "high resolution" TV's, as in 800x600 computer monitors made for presentations. I almost bought a Gateway 35" monitor once, 800x600 with the VGA connector, S-VIDEO, composite, and speaker inputs. I was planning to connect a VCR to use as a tuner, and use it as a TV. BTW, it was much, much cheaper than an HDTV.

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