Disagree with the initial premise, they have very different uses, IMO. I do like bourbon quite a bit for sipping (and Scotch as well), but I have never had a good Scotch cocktail (though I drink Rusty Nails when I'm feeling masochistic). As with Week, my go-to cocktail is the Boulevardier, and it's fantastic.
Two notes on bourbon/American whiskies with weird finishes - have y'all tried either Breckenridge bourbon (out of Breckinridge, Colorado) or King's County Peated Bourbon (out of I-don't-know-where New York)? Breckinridge I find very interesting, as the initial hit tastes like a bourbon, but the finish has a weird... I dunno, minerality, that I associate much more with Scotches.
The peated bourbon is something my boss has been talking up, but I've never seen it before and would be interested in a review from someone who's tried it.
Re: old-fashioneds, I rarely order them anymore; like Swordfish, I find the range crazy-wide. There are some very good ones and some really awful ones. You can get a shitty Manhattan, but it's not as far from an average Manhattan as a shitty OF is from an average one.