Almost everyone here seems to be slightly biased towards OSX... Whats the problem with it? Last time I checked, Apple was delaying 10.5 because they wanted to make sure it is ready for release before they release it.
You can't say that much for Vista...
Quick EDIT:
Yes, I know about key programmers being pulled off, but accourding to Apple, 10.5 is ready, they just want to make sure first, and thats a bit harder without the key programmers.