I still have my Mountain Bike, but keep it at the cottage. Switched to being a roadie just because it's so much freakin' easier in Toronto. There are so few trails around me, and I don't like wasting time driving up to a trail north of the city when I can just jump on my bike and ride anywhere I feel like.
If I was still living on the west coast like I did as a teenager, I'd probably still be all over mountain biking. I still have good memories of fast fire roads and sweet singletrack around southern BC and Van. Island. Oh nostalgia.