I abandoned drum loops a few years ago because I felt it was too limiting. Nowadays, I program my own drums using MIDI (I use Sonar 5) with a sampler (V3) loaded with drum hits. Check out Sonic Implants Blue Jay series - there's also a ton of free drum soundfonts and samples out there. Several programs out there allow you to program realistic drums (BFD, Battery, DFH, Addictive Drums, etc.) There's also a lot of articles and info about how to program realistic drum beats. Check out Computer Music magazine (
http://www.computermusic.co.uk/) from the UK as there's always a lot of good advice in that magazine.