help on a laptop purchase

For what you want it to do, a Pentium Celeron with 512MiB of RAM, and at least a discrete graphics card is all you need. 512MiB of memory isn't necessary, but it would be useful for multitasking and running Firefox. Most, if not all laptops will include 802.11b/g wireless connectivity.

Assuming that you do have a main PC that runs games, burns DVDs and has plenty of space; then you do not need a separate burner for your laptop or a huge amount of hard disk space as you can share your drives on your desktop on the network.

Again, it really depends on what you want from the laptop. If what you said is ALL you want to do, then the Celeron with 512MiB RAM is more than sufficient and there would be no point upgrading to Vista, so you don't need any expensive components like Core 2 Duos and fast graphics processors.

Jam it back in, in the dark.

I see, then a burner would be very useful and you might need to upgrade the hard disk. If you are upgrading the hard disk, buy one separately as it will probably be cheaper than buying from the vendour, and you can put the one that came with your laptop into an external enclosure.

The newest AMD mobile platform is Turion64, which is basically a Mobile Athlon64 with specified graphics and wireless, similar to Intel's Centrino platform. (Although they are a little lenient on which hardware manufacturers can make the Turion badge, unlike Intel.) Performance wise, it's competitive but Pentium M still excels in more benchmarks, and it generates more heat and therefore uses more battery than Pentium M and Pentium M ULV versions. Turion64 X2s are in the works, presumably a dual-core Mobile Athlon64 X2, to compete with Intel's upcoming Core 2 Duo Merom cores.

Edit: Spellings.

There's nowhere I can't reach.