I switched from a Dell to a Mac two months ago last week. Leopard fixed the last issue that was stopping me from switching (good mail client). The Mac is easier and more reliable, no doubt about it. It's also much better at stuff like video. Don't let the firewire port on the Dell fool you - there's a lot more to it than just getting the bits off your camera. iMovie kicks MovieMaker's ... in terms of usability, speed and stability. If you're using other softwre that may not matter so much.

Also consider the extra costs you may run into: Office, etc. I'm using Mail and iWork and am completely happy with them.

One other thing to consider is the social cost of being associated with Mac users, who can be nearly as annoying as the Ron Paul crowd.

There's a Dell sitting here on the floor next to my desk that I haven't touched since the day I turned it off.

The rumor mill says that new Mac laptops will be announced on Tuesday, though, so you might want to wait.