Also, check your oil dipstick. If that's where you think the coolant is going, it should be very high. When you do an oil change, let some of it fill a glass jar, and see if it separates after a few days. While your at it, check the coolant in the res. It might have oil in it. That is usually the best way to check for a blown head gasket.
Aside from that, I kept loosing coolant in my '91 Wrangler. Every now and then I need to tighten some of my hoses at the radiator and water pump. Might want to check those too, as the other post stated. I never see any coolant on the driveway, it leaks that slow.
1991 YJ, rebuilt 4.0L in spring 2009 at 234,000 miles, no lift yet, slightly offset wheels, 235/75/15 tires for now, rag top, sold the hard top. Over 35,000 miles on the rebuild and counting.
2006 Jeep Liberty. Nothing special, all stock.