Best source of high quality royalty-free sound clips?

I don't see a forum dedicated to audio so I'll post here..

One thing I like to do is add ambience audio to things I build.. for example a computer that makes a low hum from the fans. Where's a good place to find such audio clips? I've found a few foley libraries that can be purchased on CD but I don't have $1500+ for such collections. Is there a website that has a large selection of quality sound clips that let you preview the audio and then purchase and download individually?

Here are a couple of lists. Some of the links feature true royalty-free sounds; some have things that say they're free, but that I suspect aren't really meant to be (like TV theme songs and such), but I'm not sure.

http://www.thefreesite.com/Free_Sounds/Free_WAVs/
http://www.stonewashed.net/sfx.html

That's two. There are thousands more. Google.

Thanks, but I'm looking for production-quality audio. I've already wasted hours on google not finding much that is useable.

I did find audiolicense.com just now and this might be what I'm looking for. Anyone know of any others?

the freesound project is a very nice place to find sound effects released under Creative Commons license. Quality can vary, but there's enough things there to usually find something useful... especially given quality of SL sound to begin with.

www.sounddogs.com is production quality. While it's a pay-for site, the rates are quite inexpensive and completely royalty free. And yes, you can try before you buy for all clips, and even truncate or lower the quality of the clip to lower the cost.

I get most of my sound effects from them. They have many of the "classic" sounds, like the Superfriends death ray.

You guys rock! Thanks!!