I've never bothered with a tarp  my self, but on a couple of group trips (5 day trips with our churhes youth group) folks brought large plastic tarps, & with the group they were trip savers when (not if) it rained so I decided to get my own for my personal trips.
I know CCS makes a great tarp ( :)), but I had some points to burn at Cabelas & they had the Kelty Noaks Tarps on sale so I grabbed the 12'x12'.
It arrived yesterday, & I have to say it looks really good.  Anybody else using one?