Bourbon is a nice place although they charge quite a bit for the more premium bourbons. Tribute was $60 a glass. Also try Old Glory BBQ in Georgetown on M Street. They have a real good bourbon selection and paired with their BBQ...it's quite nice.
Scheiders in DC also has a good selection of Bourbons and Whiskey's. They also have a great selection of Wine. Their prices are so so. I picked up my last Handy from them at $60.

