Which drum plugin?

Hi. I've just recently started using plugins other than those included with Pro Tools. I've been using my Yamaha key board for drum sounds. It serves the purpose but doesn't sound very realistic. I've researched Steven Slate Drums and Expand 2 but since I'm new at this I don't fully comprehend all that I read.

I'm looking for something that won't be all that complicated to install and use and will work with my Pro Tools 9, Windows7, 32 bit system. any advice is appreciated. Thanks.