My roommate is going through the same thing.
If you get a Windows based Laptop with Vista, be sure to get 2 gigs of Ram. I don't know how well vista does in the long run, as I know Windows in the past would slow down over time, so you'd need to get the registry fixers, spy ware removers, and etc. I end up fixing my roomates computers, which have Windows, constantly. You also want
good hardware, especially on a laptop as you'll be moving it around a lot. Good hardware makes the OS work better, bad, cheap hardware will get you around it isn't as good. I think HP and Sony are good brands, I'd stay away from Toshiba. Dell, I hear iffy things. Go to
cnet.com and check out there reviews.
You also need to decide what you want to do with the computer. If you're a gamer, laptops in general are not as great, if you are surfing the web, writing documents, taking pictures, etc -- a laptop is fine.
My home computer is about three years old and it's an iMac G5. It runs great, I don't have to fiddle with stuff to make it work. It works as fast as it did when I got it, and I still have friends with Windows PC's they got new last year drooling over my computer... it just works, and to speeds along.
The new iMacs and MacBooks are really fast, the design is even better, and they work like a dream. I'm looking at getting a new iMac since I don't really need a laptop at this time. The Mac OS is a really smooth operating system and designed powerfully with an elegant interface. The new Macs use Intel Duo Core, so it will also work if you need to use a Windows program. You can either dual-boot or run Parallels (which runs windows program in the mac environment without needing windows).
The new Mac OS, due in October, is pretty sweet. An even better system and I can't wait to get my hands on.
Macs are very nice computers. The cost has come down and it is comparable to major brands. You can expect a Mac to last you a long time. And with the apple care, your machine is fully covered for three years -- getting it on a laptop is a good idea.
As for budge laptops, which usually have Windows included, there is a higher risk of them breaking down. Warranty isn't long or non existent. And, although I'm bias towards the Mac, I really don't like the Windows Operating system and I've already heard of Vista woes. The mac operating system does take a bit to get used to, but it is good.
The current Mac OS (Tiger) is great. Leopard, their next OS, is expected to come out in Oct.
Good luck, and check out
cnet, they have reviews on every laptop so you can make the best decision for you.