I have brides ask me all the time; do I really need to have a receiving line?
Proper etiquette states that if you can take the time to visit every table at your reception then there is no need to have a receiving line.
You should have no problem greeting 150 guests or less!

If you do decide on a receiving line though. A good way to keep a steady flow in your line is to have only the Mother's stand with you.
Mom's are usually the ones doing the inviting so they will know everyone and besides Dad's don't usually care about this sort of stuff! They'll take the time to talk to whom they want throughout the night.
If hurt feelings are a concern then you may also have your MOH stand in the line but that's it. Other wise you'll end up spending 1/2 your night just trying to get through this event.
By the way, a good set-up would be as follows: Bride's mom, Groom's mom, Bride then Groom