Sample Ninjas just put out a free (donations appreciated) collection of samples from Teenage Engineering's PO-12 Drum Machine.  I purchased all three of TE's pocket operators and I love them.  They are super fun and intuitive to use, and they sound amazing.  There's really nothing else that is quite like them.  

The samples are definitely worth checking out.  I'm sure countless hours went into sampling, trimming, naming, and organizing these samples.  Even if you already own the Pocket Operator, I think the convenience factor is high enough to justify the 250 MB download.  Head over to the site to download them to use in your own music! And keep an eye on Sample Ninjas, I've been told they have some really cool things in store...