Refighting the OS wars

So compilerbitch has convinced me that my life would be better if I finally caved and got a laptop. The question is what to get. If you have any views on the subject, please comment with them; I reckon I can get better information from the collective wisdom of my flist than from someone who's trying to sell me stuff.

My requirements: reliable; not unreasonably expensive; able to run a wide range of software; not too difficult to use; wireless card and preferably normal modem as well; ability to transfer data between machines easily; compatible with the rest of the world (especially work-wise, but in general too); CD rewriter and DVD player would be nice; ability to play games, mostly of the retro kind. I don't really care about the latest ultra-fast processor, or flashy high-res graphics, or fantastically lightweight.

I need to choose an OS, and a make of processor etc, and whether I should look for something second hand or buy new, and once I've made the decision, where is a good place to get it. And I realize I'm basically inviting a huge fight here, but I think I might find it informative, so feel free.

( possibilities )