Stacey,
If you all enjoy and/or crave time by yourself ( my husband and I do!) then I vote for the B&B or an overnight trip to somewhere...we went for a weekend to a nearby resort for our 10 year anniversary last summer and it was SO NICE to be alone... it was the first time we'd gone away since our honeymoon! We didn't do a lot, but we enjoyed sleeping in, naps, no schedule, etc.
Hope you have a great anniversary!
Lindsay