Firstly, the internet speed depends mainly on your broadband, not your pc.
You need to decide what is important to you in a laptop:
Size - do you want to carry it around a lot? If so, you need a smaller screen and weight will be important. If it's to be a desktop replacement, then you can go as big as you like.
Applications - what do you want to do? If you want to play high end 'gamers' games, or video editing, then a laptop is probably not for you.
You need at least 2gb of RAM to cope with Vista, and the larger the hard drive the better, although external usb hard drives are cheap enough now.
Do you want a dvd burner? Not all laptops, especially the very small ones, have a dvd drive.
In my laptop I find 3 usb ports to be the minimum I can live with; the card reader is very useful and I would like bluetooth (mine is over 4 years old and doesn't have it).
You may want a built in webcam (I don't)
There are plenty in your price range. Find one you like the look of and print out the specs. Use that to compare the specs with others. Doing it online is so easy.
Try and look at the one you want in the flesh before you buy - you may not like the 'feel' of it at all.
I would rather spend a few pounds more buying from a shop (online or high street) that I feel confident with, rather than an obscure one that seems 'to good to be true'.