Sooo, I have a Mac desktop now. Actually, I've had it for a little while, but I think it's worth mentioning here because I transfer all my digital work constantly between that and my Dell laptop. So far, I've noticed that colors show up noticeably duller on the Dell than on the Mac's screen, but I keep double guessing myself on which monitor needs to be tweaked.
Testing, testing. Color testing: does the background look more gray or green? (answer: It should definitely look green)