I don't see why it would be much different, even though hard disks and RAM are getting larger and faster their differences relative to each other are still the same.
I think the 2 to 2.5 times trick should still apply today - even though we have more RAM than before current software itself requires more RAM and so you end up dipping in to the swapfile anyway. If you have plenty of ram, 512MB and up and use mostly old games then you won't need to have a large swapfile, but ram greedy games and apps will.
That is, if you have more RAM than the current standard of RAM usage (recommend requirements) then you only need a swapfile equal to the amount of RAM you have. If your specs are on par or older than todays requirement's then make it 2-2.5 times the RAM you have. The size of harddisk's these days means you won't (probably) ever need the space your swapfile uses.
To how much of your swapfile is in use check the system monitor program like that guide says. I'm using my computer from a fresh boot up right now so none of my swapfile is in use.
After playing some resource hungry games for a while check your swap file usage, and adjust the size accordingly. I don't think it'll be near the 2.5*ram limit, though. Let me know please.
Didn't know about the outer track trick, so thanks for the link! Shame I can't use it - theres no chance in hell I'll download 37MB on my dial up just to move my swapfile!
