Everybody has mentioned almost every other window in the UI to death, so I'm not going to mention it again, other than in passing (I'm near-sighted, using glasses). Where it is a huge problem for me is in menus like the Key Bindings. The font used for the keys is basically illegible on a 32" screen (Using a RCA TV), and is just a couple of pixels on my laptop screen.
And I'll definitely throw my support behind unifying the fonts.