when the upload section was launched here i don't think anyone realised just how huge it would become. so the current system is not very efficient at this scale, as you've noticed. never fear though ; we are currently examining the best way to redo it to optimise the upload, download and browsing features. it won't happen tomorrow because it's quite an intensive job but we are working on it.
in the meantime don't forget you can also sort by format and by genre, in addition to searching / browsing ; that should help to narrow things down a bit. and maybe other people can add their useful tips as well.