Here's one spa treatment your groom won't be able to resist: the hot shave. It makes an excellent gift for your hubby to be or any of his groomsmen. Just think of it as something for him to do while you're off on one of your many pre-wedding pamper sessions (because trust me, the chances are slim that he'll join you on a mani/pedi appointment).
My favorite spot: Freeman's Sporting Club in NYC. The boy's club vibe will make him feel instantly at home, as will the old-school barber chairs and men-only clientele. They also offer haircuts and hangover treatments -- love that! Send your groom in, and let me know what he thinks. And if you're not in NYC, don't worry -- there are tons of places that offer this service, so just do a quick google search in your area. If you come up with something fabulous, tell me about it!