IK Multimedia is currently doing a sale on SampleTank's Xpansion Tank sample libraries in a group buy. I got in on this when it was 4-for-1 libraries and so many people have gotten in on it that everyone in the group buy is now 7-for-the-price-of-1. With the purchase, you'll get the SampleTank XT, which is the "lite" version of SampleTank XL for free along with it. The offer is good until 5/31, and the plugin is good for VSTi/DXi/RTAS/Core Audio so everything from Cakewalk Music Creator to Pro Tools HD to Logic Studio is able to use it. If they make it to 6000 participants, they're going to expand it even further. You can choose from the sample libraries and audio loop libraries, in any combination of the two types.
I'm not describing it well, but it's worth checking out if you like good samples (made by Sonic Reality) and loops. http://www.ikmultimedia.com.