I had to buy a Macbook Pro when my G4 Titanium started to crap out. I don't see a big difference with the Duo Core, and the new Mac doesn't have a PCMCIA slot - just the new (improved, read: you have to buy new stuff to fit it) ExpressCard 34 slot. Keep in mind, I used my G4 for work and travel and got a LOT of use out of it... certainly got my money's worth. Someday I may try Parallel to run a Windoze program if I feel I'm getting low on my frustration levels.
Like most Mac machines, this new laptop is well thought out, easy to use, and very functional. As PCs and Mac get closer to the same, I still give the edge to the Mac.
My 2¢... but I am very biased towards Macs; I also think C-Dorys are the best trailerable powerboats, trimaran sailboats are great, and classy catboats should be at everyones' docks; cats are easier on a boat than dogs; warm is better than cold (except for ice cream); laughing is better than frumping. Oh, and retirement is pretty cool, with the only downsides being no anticipation for the weekend and if you want to buy a major toy, you have to think about what that's going to do to your "what if I live past next year" account.