I just bought a used-in-excellent-condition Schwinn IC Elite through the classified ads in my area. It's an $1100 bike and I paid $400. I wanted a gym quality bike and this is just that. My daughter goes to Golds Gym and they have the Schwinn IC Pro. Mine is the upgrade to that.
Google "spin bike reviews" and you should get a good idea of some good spin bikes and what to look for.
Here are a couple of links that helped me.
http://www.fitmoves.com/IndoorCycling/spin-bike-review.htm
http://www.fitmoves.com/IndoorCycling/schwinn-spinning-bikes.htm
I also have a Tunturi Stationary bike (which was quality in it's day) and this new Schwinn IC Elite is much much sturdier and quiet and it is super easy to adjust to both me and my husband. I also like that I can clip in the pedals now. The Stationary Bike puts me in a more upright position whereas the Spin Bike puts me in more of a bent-over real-road-bike-feel position. You can also stand up and pedal very comfortably on the spin bike (love this).
So, my advice is to first look for a used gym quality spin bike (in your area if possible to avoid shipping costs) vs. a stationary bike. You can find a bargain and spin bikes are tough and should last a very long time. Mine shows hardly any wear and I was told it was used in a small gym that went out of business and got about a months worth of use.
Look for Schwinn, Lemond, Startrac. I'm sure others can name more brands, but those are the brands I was looking at.