Most leather sportcoats look as douchey as the people who buy them intend to look. (And I don't mean they aim to look like douchebags, but they intend to go for the look that you or I might think of that way). However, I think they're one of those menswear elements for which there is a narrow range of potential for not only avoiding the douchebag look but for achieving a very stylish outfit, and this depends upon the jacket itself (the cut and type/colour/finish of leather) and the rest of the outfit worn with it. In general I believe that quite extravagant garments can often be brought back to earth if the entire ensemble is carefully chosen.
STF has some nice Attolini leather sportcoats.
I think those examples illustrate what I said. Nice cut, nice leather (no shiny black finish) and the effect is kept in check with the more conservative clothes underneath. Both could be worn with pants, while in neither case would you stray into douche territory if you chose to wear jeans. (as long as you didn't go with an over-distressed pair).
Now I'm back to drooling over those Attolinis and wishing I could afford them. Thanks a bunch.