According to Jeroen van der Ham:
You are right, the problem is with Monaco, other fonts do display the italics better. But I must say that I really like the look of Monaco.
Bitstream Vera Mono has an italic version.
But my opinion of anti-aliasing still stands. I have no idea why anyone would want anti-aliasing, because all the letters seem blurred. (Perhaps
Well, I don't know how far your screen is from your eye but AA with Vera Mono doesn't look blurred and is very nice (to each his/her own of course).
Most monospace fonts w/o AA look just... not right.