Well, I do a bit more than surf the net and word processing, but most of what I do is more CPU and memory bound than graphical (scientific programming, modeling and simulation, hardcore number crunching stuff), but my real workhorse stuff is done on an 8-core 16GB RAM MacPro. So really, this isn't much more to me than being able to say "OOooohhh NEW SHINY!!!!!" especially if it gets an enclosure redesign.
LOL I love NEW SHINY! That's the same for me. I just bought a new 24" iMac about 7 weeks ago (my first mac computer) and I've loved it so much I need a laptop to go with it. But any real, major work I'm going to do is going to be on the iMac, not the 13.3" screen. So the macbook for me is just going to be to dick around with. And it's nice to have at school to type things up. But yeah I'd say, unless you want the latest and greatest, keep the current. I think everyone is expecting a major overhaul next May of the MB, so like I said, if you don't want the latest and greatest, at least hold off until May. I don't know about the Applecare... when 1 year is comming up on my iMac I'm not sure what I'll do. I guess if I can afford it, I'll get it.