After seeing Shred-Well from The Grime I was totally impressed with the way trick track riding is going. There are lots of lines and lots of big stuff, as in 15-stair big.
I also really love when riders use their environment, pulling tricks where you never expect it. That's part of the reason I switched to singlespeed. Riding is about having fun as well as commuting. When I'm riding fixed I feel as though I'm just pedaling. If I were to try a trick I would have to slow down and make sure my feet are in the right position. With a singlespeed I don't slow down, and with 35mm cross tires I plow through whatever I want, allowing me to use even more of my environment, the non-paved part.
Really though, fixed, singlespeed, whatever. It's practical. I can commute, I can do tricks on the same bike.