This question feels like the same type of "what would be your dream car if money was no object"? I simply don't enjoy playing in those kind of (mind) spaces, its just not real. So my reply is going to be based in reality (of which, my 'dream answer' would lie around there too). I absolutly love the BCBC type of trail riding. I love tight techy narrow off-camber single track that makes you stay focused. The stuff that you have to thread together 2-3-4 moves in a row so that you can keep progressing down the trail. In this same category, I have to give Thumper the nod also. When the weather is really nice, the trail bed is perfectly tacky, and the canopy is clear...I luv, love, LOVE, riding Thumper. There I said it!!.... LOL
It'w worth noting though, when I go to Bentonville and ride some of the fun, machine-built, fast and flowing stuff (ex: deep into Little Sugar)...I find myself getting to the bottom to pause and laugh out loud at how much fun those sections of trail can be. Simply put, good single track is good signle track.
Cheers,
CJB