I'm using a Hori Real Arcade Pro with sanwa stick+buttons and a replacement octagonal gate on the stick. I usually sit with one leg crossed but it falls asleep after a while. If I sit on the floor with my legs crossed, I can play for hours, though. If you're serious about getting a good fight stick, get a Real Arcade Pro - the EX sticks seem like a waste in comparison.
Things I really like about this game: having two super meters, the decent accessibility (my friends are getting into it), the great music and general Street-Fighterness.
Everybody online plays as Ken. Lol. He's not even that good! I like playing the weird guys like Abel, Dhalsim, and Vega - people don't really know what the ****, even though they aren't really high tier.
Blarg Sagat is top tier. How very CVS2.