I've bought a number of cars in my driving lifetime, and have eventually sold them in favor of something else - though never did I feel the pangs of buyer's remorse. This time around; however, I bought a Mac Pro, and have really felt like I made a mistake. It's an amazing machine - which gets used about once a week. I needed to replace my ailing home machine, and I could've done so much more cheaply, but I already had a nice LCD monitor. Now I regret the whole shebang, because I could've just gotten an iMac (or better yet, replaced my two and a half year old MBP with a new one - I bought the Mac Pro a week before the updated MBPs were announced). So yeah, that's the biggie right now. What are some of your purchases that made you wonder wtf you were thinking?