We're actually using Gurps, but the whole system will be in the GM's hands so that it's all "under the hood" so to speak. The player says "I want to do this" and the GM goes "Roll XdX, if you get higher than X you are good." Character creation will be played out too, so the player says "I want to spend my time training with a bow" and the GM marks down the appropriate ranks in archery (or whatever skill governs bows).
It's that way so that even people not used to the system we choose (or who have never worked with a system) can play.