A while back a friend and I were lamenting a crappy Manhattan. I believe my rant was something along the lines of how there was too much Vermouth and not enough bitters, and she came up with the brilliant idea of carrying a small bottle of Angostura in her purse for emergencies. While I haven't gone quite that far (and I'm half sure she was joking), I do think the bitters family needs more attention in the home cocktail arena.
For example: celery bitters by Scrappy's. Excellent with gin or in a Bloody Mary or just about anything in the warmer months. Kind of expensive, but worth it. If you buy it at The Boston Shaker in Davis Square, they'll probably let you try the chocolate flavor, too.
Then there's Regan's Orange, concocted by Gary Regan in the 90s since he couldn't find an orange bitters he liked. Not as expensive as Scrappy's, and more widely available, too. It's great in the aforementioned Manhattan or anything with whiskey, really. But most bitters are good in a way you might not expect.
Chez moi (sorry, we started Classical French cuisine in school today) we like a drop or two of bitters over ice, topped with seltzer. It's tasty and a little special, you know? Plus the seltzer bottle makes such a satisfying FWoooooSHHHH! when you screw in the CO2 cartridge.