More of the same
Bought a Specialized Epic in '03, my first FS bike. Loved it, it's a great bike. Then last year my buddies convinced me to try SS. Built up an Ionic JR. In the last 9 months I've ridden my FS twice. Not only is the rigid SS more fun to ride, it's actaully made me a better rider. (forces you to pick better lines, hold momentum, etc..) I'm currently building a rigid SS 29er and recently bought a SS road bike. My guess is the FS will be on the chopping block pretty soon.
As they say, horses for courses. For most of the local trails here in Dallas, the rigid SS is just fine. I may build a geared HT in the future but for right now, I'm really liking the simplicity of the rigid SS.
Funny side note: even with 27 gears, I never felt like I was in the right gear. With one gear, I'm never in the wrong gear.