TVs are almost always 16:9 rather than the 16:10 ratio of computer screens, so I'm suspicious that your having it set to 1920X1200 (which is 16:10) is the issue. Specifically, if it IS 16:9, then that means the TV is being forced to rescale the image to fit, which could well blur crisp lines. There should also be a 1920X1080 resolution available, which probably matches the TV, and may look better.
[Edit: My second suggestion was that it could have to do with a low-quality VGA cable, but you replied while I was typing, and if it looks ok in Ubuntu, that's probably not it.]
Third: Did you check the font smoothing style? It's in the "Appearance" pref pane. Having the wrong one selected could well make text (and ONLY text) look blurry. Note that changing it doesn't take effect immediately, only in programs launched after the change. You should probably log out and back in to make sure.
Other things to try: The TVs with a VGA input I've seen usually have a number of adjustments to the position and actual resolution of the image; see what your TV has and if you can mess with them. Also try downloading an HD "test pattern" that has an image of alternating dark and light one-pixel lines; this will let you check if you're actually getting the resolution you think you are--if so, all the lines should be visible. If they are blurred together, there's rescaling happening, which could also affect the quality of text.
