FWIW, there was some discussion about turning on antialiasing in various parts of the product in the past. It seems to be a divisive issue. Some people seem to be entrenched in the position that antialiased text == blurry text. Cough... luddites...
When JDeveloper eventually moves on top of Java 6 (which I hope, but don't know for sure will happen for the 11 release), anti-aliasing will be on by default (assuming it's your OS default), and it will be the spiffy new sub-pixel antialiasing Sun implemented for this version of the JDK.
Thanks,
Brian