Abe and bookfinder are good. Also Antiqbook.com (although their database is sometimes outdated and i get a mail back once i na while that a certain book has already been sold.)

Alibris.com and Biblio.com I also use. So far all with 100% satisfaction.

__________________
"Facts are meaningless. You could use facts to prove anything that's even remotely true!" - Homer Simpson

(banner by Otto)
www.basher82.nl