Birdcat is right on, recom

Birdcat is right on, recommending Digital Juice. Also, somewhat less sophisticated stuff is available from Rab-Byte. IMHO though, RB is looking a bit long in the tooth and nowadays much of its stuff might come off a bit cheesey.

Digital Juice is expensive, relatively speaking, considering that like many of the royalty free music libraries there might be only a few things on a few occasions that something in any one set will work out for your purposes. If you have the resources to invest, over time, in the entire collection, and the client base and business to warrant, then you cannot go wrong with DJ.