We had ours at DH's brothers house... it was a potluck/BBQ thing and turned out great. Our families hadn't really met yet, so this was a great informal and social way to meet. I think a picnic or a park thing would have been fun too!
Since there are going to be soo many people at our Rehearsal and Rehearsal Dinner... I think we are going to have just something catered to my Mother's house. It will be in the evening, so I would love to hang white Christmas lights and maybe some candlelight on the tables.