I used to be a hard-core vi user (none of this vim crap), complete with elaborate vi macros that interfaced with external spell checkers or text formatters. I began to waver when I saw gdb-mode. Shortly thereafter, I saw the writing on the wall and switched to emacs (by which time, emacs wasn't as widely known as "emacs makes a computer slow" or "eight megabytes and constantly swapping"), and promptly had a month-long email exchange with the maintainer of viper-mode, which now does a passable job of immitating vi keybindings. (You can take the man out of vi, but you can't take the vi out of man.)

I haven't tried many of these PC editors, but I have played with many of the IDEs (PC and otherwise) that have come along. I like some of the autocomplete features (yes, you can do it in Emacs as well, but not as elegantly), as well as the drop-down help that's integrated with Javadoc. Did you forget the order of arguments to a method call? There it is, right below your cursor. That's pretty cool. Having your class hierarchy in a sidebar, allowing for quick browsing is also moderately useful.

Beyond that, I'm always striving for ways to avoid using my mouse. Keyboarding just seems more efficient.