can i let my boyfriend answer this one? he helps people with this sort of things all the time, so here goes:
ok, i'm going to give this some length since i think it's a big decision and i think i can offer some useful suggestions on it. i might repeat myself a bit, so forgive me in advance. (otherwise i'd have to revise and rewrite and...)
in general, mac has excellent engineering, and the operating system is vastly superior, as is is the integration when you want to get creative with music and video. mac also tends to be pricier initially and for bells and whistles (like extra ram), and can be harder to find friends who can, ah, donate a copy of a program.
the reason i would choose the dell, though, is because dell offers coverage for accidental damage. applecare doesn't give you that. in fact there's an awful lot of dissatisfaction with applecare, which is bad enough, unfortunately, that it pretty much balances out the superior constrution. yes, people have less problems with them due to the better design and production, but problems still do crop up, and when they do, the time and frustration factor is so much higher.
some stores offer you accidental damage coverage as well, including on macs. it's only worth it if they're very good about honoring it.
if you get it, be very assertive. they really like to push it on you, and once they've got your money, can be a little reluctant to make good their end - cut to the chase and explain you're forwarding copies of your complaint to x, y and z.
(long aside here: a friend in the us who bought from best buy had a problem - a cracked case, when all the similar models would crack just from normal use and it was a known problem. since it was still under manufacturer's warranty, the store just mailed it back to compaq and it took seven weeks before compaq reported the problem was his fault and they wouldn't repair it for free. he asked them to just send it back and he'd live with the cracks, but they refused to send it in that condition, and he had to give compaq hundreds of dollars for a new case before they would return it to him. he complained to the better business bureau. months later, someone from compaq called and asked him if he'd complained to the bbb and sent him a full refund, but hardly what you want to go through.)
for a laptop that you're going to move around a lot, accidental damage coverage is very important.
but... consider another option: if you're using it for taking notes and web surfing/research, there's no need to get the latest machine. i have one several years old and it does well at everything except video/photo editing (and even that i can make work somewhat... but slowly).
for the price of the extended warranty on a new macine, you can get a used one that you won't have to worry about so much. if you end up needing more power or whatever later (like if you do get into video editing, which even a new laptop want be great at), you can get a desktop, which will be much more bang for the buck. or you can go with a newer laptop when you really need it.
if you go used, look for a solid machine from a reputable dealer, and look for a battery that still holds a good charge (they get weaker the more they're used) or plan to replace the battery (and dispose of the old one responsibly - very important as they're have a nice supply of toxic heavy metals).
i can tell you the one i got mine from if you want - an ebay store that sells off-lease thinkpads. it's never had a problem despite some rugged travelling, and came with a battery that was very solid, and still is two years later.
certain brands are less solidly built and will come apart even under normal use. sony viao notorious for flimsy construction, and that's backed up with terrible customer service. (in fact, sony is a brand to avoid for most products, with a very few shining exceptions.)
do a little research on the complaints people have had about different models/brands.
just think about what you want, and then ask yourself what advantages a brand new machine really offers you.
for the things you describe, the answer seems to be none. an older machine will be much cheaper, and you'll also worry about it a lot less (if it does get damaged or stolen - if you leave it unattended for moment it will - you're out a lot less and since you backed up your data regularly, it's not so hard to replace).
that can make it even more useable for you, since you might take it with you at times the risk of loss/damage would make you unwilling to take a much more expensive model that you'd feel you have to baby more.
unless you really know why you're getting a specific model, wait until you have a specific need, otherwise you're overpaying and not getting any more satisfaction for it.
the thinkpad t23, which i have, with the 30 gig hardrive is on offer on ebay for $349 with buy it now. the t22, slightly slower but you won't notice it much, is $249 (of course, you'd want to query about the battery). you could get them for less, but for $249 you can do everything you need.
we have a couple older machines and rarely do feel hindered by them. in fact, we appreciate that we can just shove one in a bubble-wrap padded envelope (protects it, and it looks a lot less attractive to theives who tend to watch for their opportunity when they see an elegant leather laptop case) and take it wherever.
i copied, below, a bit of the blurb from one of them. you'd certainly be able to take notes, watch online videos and dvds, and do all the web surfing you like. if you need to run dragon naturally speaking, you'd want the t23 and an ram upgrade, since it requires 1ghz processor speed and 512 ram.
unless you're playing the latest games and doing the video stuff you won't need more (and again, if you do need more, you're still much better off saving the money by going with a cheap laptop and using the savings to get a good desktop model that'll be far more satisfying for those uses).
so, those are some ideas, and i hope they're helpful.
excellent condition, ibm thinkpad t23, 1.13 mhz piii, 256mb, windows xp pro, cdrw/dvd
ibm thinkpad are the most rugged and well made laptops out there and are well know for it. made for the business traveler with the stringent needs of a mobile lifestyle in mind.