Thought I'd help migrate the discussion on dev environments from the other thread to here. Feel free to repost, I'd hate for anything to get lost in the ether!
We're a Mac shop at EMPAC, and I use one for my consulting work as well. Though we allow our developers the freedom of tuning their own environments, most of us use Eclipse (or some fork of it). Paired with XDebug, it really cuts down on the number of blind dpr()s, and drush obviously makes just about anything Drupal-specific that much easier. As for revision control, we've been primarily using bzr, but are slowly migrating over to git for new projects for improved compatibility with d.o infrastructure.
I'm curious - what does everyone else use? Those who've had trouble getting a local environment up and running should feel free to chime in, too - I'd be happy to help!