Dammit, I still run XP on my laptop. The latest Chrome and Firefox run just fine on it.
Not that I ever run IE anyway, unless something I need to do has been written to require it specifically, but seriously, Microsoft - your marketing team should not be writing the specs.
You really shouldn't run XP if you have the option not to. The security structure in XP is outdated and, frankly, dangerous. Vista and 7 are vast improvements. Every time I see an exploit that targets XP I get a little giddy because I know I won't have to deal with ASLR and I have a much higher chance of getting an Administrator account.
Microsoft is absolutely right to encourage people to switch.
My poor old laptop won't run 7; it has a hard enough time keeping up with XP. And it's behind a careful firewall at my router - well, except when I travel.
My desktop runs 7 and I love it, but it's a much newer machine.
So you're taking a risk -- you should just recognize that and admit to it. I'm not sure why you're qualifying. I may have a laptop from 1997 that can only run Windows 98 comfortably but that doesn't make it secure or a good choice for security in 2010. Sometimes you just have to spend money and upgrade.
By the way, a newish 2.6 Linux kernel with WINE should do most of what you want and approximately the same system requirements. Your mileage may vary if you have an obscure Windows-only program.
I do, in fact, have more than one obscure Windows-only program - the entire translation industry is Windows-only.
I'm not sure why you think I "have" to spend money and upgrade. I can't lose data, and I don't keep sensitive data on a laptop - the worst that can happen is that I have to reinstall the machine if it's beyond rescue.
Not that I ever run IE anyway, unless something I need to do has been written to require it specifically, but seriously, Microsoft - your marketing team should not be writing the specs.