Well, that could be an individual thing. For example, I have a 19" CRT and use 1024x768 with it, and before that I used a 22" CRT with 1280x960, and always had to zoom in to read text on web pages with both monitors. Viewing distance usually between 2 and 4 feet.
And at the moment I'm looking at buying a 32" HDTV (1080p) to use as a primary computer display. I tried my 32" HD-Ready TV (1366x768), and thought that was fairly OK, so I shouldn't have any problems with 1920x1080, even on 32". And I still have a foot or two to spare on my desktop, so 5-6 feet viewing distance is attainable, if needed.
But it's true that when sitting on a close range (and if you have better than average eye-sight*) you might be able to distinguish the pixels apart, which lessens the "immersion" effect. But this is something you should find out for yourself through empirical testing. I know in my case, I would probably have to set a fixed 150-200% zoom on web browsers for a 24" 1920x1080 display.
(*): I don't consider my eye-sight to be bad or anything, I don't even need glasses.