I identify with a lot of what you guys have already mentioned. When I was a kid, I saw the Bigfoot episode of "In Search Of" with Leonard Nimoy. I was totally afraid, but we lived in the city so that went away ;-) Not prime BF habitat after all.
It sort of remained in the back of my mind, but I didn't really give it much though until I started hiking a lot, a couple of years ago, and with a vivid imagination I started thinking about BF again. Then I ran across all of the websites, of course.
As for BF, it most fascinates me that it's likely to be a proto-human or a co-evolved hominid/hominin. How cool would that be! Yet, it would also be different than us and be able to give us perspective on our own evolution and existence--it's like finding alien life, but right here on our own planet!
As an avid outdoorsperson, there's also the fascination with living one's existence in nature. I'll leave you with this quote from, IIRC, a former park ranger:
"He's a monster, he'll eat anything, alive, dead, fresh, rotten.... He's a survivor... mobile, quick, fast, and strong.... Anybody who sees a slow Sasquatch is not in the ball park.... He's got no limits, climbs any mountain, swims any river. He's got no barriers.... Not an endangered species, thats us.... He can pull down big game on the run or by stealth, like a cougar.... He can lay down a light track or spring like a deer.... Has a lot of humor, yet restraint.... Rocks cars and cabins, but lets folks go.... We agonize, he couldn't care less.... An opportunist at the top of the food chain, in great shape--he's got it made! Adapted to cutover lands, lives a good rugged existence.... He's got no need for wages, lives off the fat of the land, and pays no taxes!"
Bigfoot's got it made! :-D