We always have a family party for my kids. but they get to choose each year if they want a friend party or not.  Usually if they do it's just 3 or 4 friends.  And I keep it very low key.  My daughter's birthday is coming up and we're just having her friends meet at the park for a few hours.  We'll have cupcakes and juice and play a few games and then they can just have fun on the playground for a while.  I don't even usually do treat bags for the guests (is that horrible?)