Back in the day... When I got into MTB there wasn't even suspension forks, so the choice was simple. I'm kinda glad it was though. When I look back on the HT's I've ridden, I realised how versitile MTB's can be. Off the top of my head on a HT i've:
DH,
FR (ish)
DJ
Cycle Tour'ed overseas and in Australia with Paniers
Mucked around doing Trials.
Seeing who can make it to the top of a knarly climb without putting a foot down.
Used it as a daily commute. (ST + 10kms of bitumen).
Worked as a courier on it, averaging 90kms a day.
Have done Enduro races
80km+ road rides.
Epic MTB rides (getting out in the great Aussie bush including long road sections to get back to the car).
Because I was riding a HT when I discovered a new experience in MTBing I wanted to try. Cycle touring? no worries, those holes on my frame are panier mounts! If I only had a FS it would have severly limited my experiences. I am now fortunate enough to have several bicycle in the shed. But if I could only have one, it's gotta be HT. Sure a FS is better at some aspects, depending at what it's been designed for. But the beautiful utilitarian simplicity of a quality trial riding HT is impossible to ignore.
*disclaimer* FS are getting lighter, more efficient and longer travel. Hot laps being punched out by Trent Lowe et al on 6" FS Yetis at Enduros races indicate that we are getting closer to the holy grail, a bicycle that does everything. Pity we already have discovered it, it's called a HT! But I like you, want to ride faster, lazier and with more room for error so the search continues...