I'm using VGA for my connection and its okay... the resolution I have to use for my connection is 800 x 600, which obviously isn't the same as the other resolutions, but it's good enough (I can actually read the text while sitting on my couch). I've tried other resolutions, but the screen never quite fits right. You would expect that HDMI is better, but I've heard that you still have to use 800 x 600 resolution for that connection. While I haven't heard anything specific about DVI, I would actually expect this might have the best connection for computer to TV as you get the digital signal, and might end up with different resolution options, but again, I don't know for certain.
I also tried looking around online and haven't seen too much for DVI connections on TVs...
Another thing that seems to be a bit of a concern is burn-in. Remember the little taskbar on the bottom of the screen? If you are using your TV as your screen for long periods of time, it could be an issue (although less so for LCD screens than Plasma screens).
The only other thing I'll mention is that I have yet to see a TV give as good of an image as a regular LCD monitor. The images just aren't quite as sharp, but to be honest, for movie viewing or playing games, I don't notice the difference unless I'm really looking hard!
Ultimately, I think any of these three connections would be fine for most uses.
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