We can't know what's the best tarp for you - but I will second (and third) the vote for OES ( http://www.outdoorequipmentsupplier.com )

I have 2 tarps from Brian (one sil nylon, one cuben), and the quality of materials, and workmanship cannot be beat for the price. If there's one thing I've learned through the years is that you don't want to compromise on your quality of gear - you only get what you pay for.