I dunno if sitting is bad or not -- but ever since I got a fitted desk and put a Deskcycle under it I've felt super great. It's a bit awkward always being a little bit sweaty though (I put in ~50 miles a day).
If interested, I made a little tool to gather cadence data on a computer instead of using the provided monitor: https://github.com/lfowles/deskcycle
> The precision machined flywheel silently spins at 14 times your pedal speed. The high inertia of the flywheel helps keep the pedals moving at a smooth pace, sort of like a mini spin bike.