How many fonts do most designers keep installed on their system?

I know that after 500, Windows 2000 warns you that your system may suffer a performance penalty, so do you keep uninstalled fonts in another directory, and only install some as you use them? Do you use a font manager program? (If so, what is it?) Or do you just not have that many fonts?

(And if you ever want a bunch of fonts, just buy a copy of Word Perfect - it came with a ton of them in WP Family Pack 2, when it was WP9.)

Just curious.

Thanks,
David