ctimrun, I live in Paducah, KY, which is about 1.5 hours north of Clarksville. In-between us, is KY Lake, and Barkley Lake. The watersports scene here is growing. Not nearly as large as Nashville, which is closer to Clarksville, but still a great lake that's huge. You can actually use the river system to get from Nashville to KY Lake.
I've been on Hickory Hollow Lake in Nashville, and it's big, but seems to me to be very crowded. Lots of people on here live in that area, so they can tell you more about it.
If you head this way, I'll be glad to show you around my area. I can show you the lakes area from my boat, or whatever you'd have in mind. My cousin is a realtor (
www.stevekeiler.com) and may be able to help out for the Paducah area. There are a few small towns in between Clarksville and Paducah, which would be perfect for a large piece of property for the horses. You won't have a problem finding property that's zoned for them.
Let me know if I can help out in any way.