+100 for Geist. It's incredibly powerful. You can pretty much do all of the drums and percussion for a song in one instance, and build your arrangement in there too. I find that in a lot of cases its in built effects make it possible to mix the whole thing within Geist without using any additional plugins. You can edit and shape each sample to your heart's content.
And if you're into slicing beats from loops, Geist makes that a breeze too. The program has obviously been designed by people who know the ins and outs of beat creation. While there are some improvements I would make, they aren't show stoppers and I believe Geist is the best drum VST I have ever used. It's a pleasure to work with. There's a lot to learn because it's an incredibly powerful program, but luckily it comes with one of the most well thought out and presented manuals in the business. Can't praise it enough.
Although dub is entirely right about it not displaying the kit you are playing. That's a pain - but I wonder if its due to the fact that as soon as you swap out any of the samples (or otherwise edit them) it's not really that same kit? But I digress.
Oh and the browser is pretty good too - it makes searching for samples easy, and you can favorite folders and also "shortlist" loops and samples for a project as you're browsing.