I've done a little concoction of butter, brown sugar and bourbon before. It was good. But I'm not sure the bourbon made a significant contribution when the butter and brown sugar are good on their own. Although if you're serving it to guests you can put the smallest splash in the brown sugar and butter just so you can mention it in the name and entice them. It sounds fancy.
But ultimately I like salmon with just a little salt and pepper. I agree with just drinking the bourbon.