I've written before about the great job that Ed Forbes does on his blog writing about different cocktails. Since I started reading his blog, I've tried making one of his cocktails each weekend. Here are the ones I have tried so far, along with my thoughts on some of them.
Scotch sour- This is pretty much your basic whiskey sour, though the scotch does add a slightly different flavor. I have to admit that this was the first whiskey sour I had ever made not using sour mix. It was pretty tart; I think the lemon could be cut back a little bit.
Knickerbocker- Basically just a gin martini (redundant, I know) with a dash of sweet vermouth. I usually have a hard time drinking martinis, but just the dash of sweet vermouth made this a very pleasant drink.
Black Feather- I tried this one last weekend and really enjoyed it. Maybe a little heavy on the cointreau, but that's not necessarily a bad thing, but there is a good depth of flavor here.
Between the Sheets- I usually avoid drinks with silly/sexual names, but this one was pretty good. I'd suggest boosting the gin a little bit.
Boss Tweed- This one was good as well, though I would cut back on the lemon juice as I found it somewhat overwhelming.
Satan's Whiskers- This was really a nice drink as well. Pretty well balanced.
Check out all the rest of Ed's cocktails over on his blog. I'm sure that you can find at least one (or two, or three) that strike your fancy, assuming you have a taste for fairly classic cocktails.