First - my congratulations to choosing SONAR X1. THis is also my main DAW and I think it runs Cubase, Reason and a few others competely over.
Second - the best drum creator is a drummer who PLAYS the tracks, whether that is through a vst sampler or a rigged acoustic set. Programming drums or just putting in the bundled MIDI-files is pointless if you need it to groove.
The best samplers/sound banks/drum software though - in my opinion - would be Superior Drummer and it extensions, Ocean Way drums (Sonic Reality), and probably Mixosaurus (monster that only comes preinstalled on a fat HD). Heard a lot abut Steven Slated drums also (SSD) so they may be worth looking into.