I had to make a big decision about a laptop last year. I originally bought a Sony and thought it was ok but I had nothing but problems from the store i bought it from. PC World are the biggest cunts on the planet.
Anyway I didn't like vista and with all the hassle i had I decided to get a refund. Then I bought a macbook off ebay and it was one of the best decisions i've made. They seem to work on common sense and I have had no problems whatsoever. You can have as many windows open as you want and it still doesn't slow down. Plus the software you get like gargeband and imovie is really fun and easy to use.
The only shame about macs is that alot of companys only make programs for windows so I have had to install windows on it for the CAD stuff I have to use at uni. You can download all these things for free anyway
http://www.opensourcemac.org/