Guide to buying spin trainers
A discussion on the various types of spin trainers available, and why you may want one
What indoor trainer to get?
There's two main types of spin trainer (except rollers, which are more about technique than fitness). Exponential resistance, like wind and fluid trainers, and linear resistance, usually magnetic resistance trainers.
If you want to get road "feel", you want exponential resistance. The good news is that wind trainers are the cheapest, but, they're very noisy. Around $200 or so will get you a wind trainer. Mag trainers are quieter, but they don't offer exponential resistance levels, so they have dials to set resistance - depending on what you're trying to do this may be ok, but in general, I believe they're inferior to exponential resistance trainers. They have the one advantage of being quieter than wind trainers. Mag trainers vary from 250-odd to around 400, usually depending on what sort of adjuster they have for their resistance level.
Then there's fluid trainers, which are the best of both worlds, exponential resistance, and reasonably quiet. It's probably better to say "less noisy", as they all make a racket. A fluid-2 will cost around 450-550 or so.
Some mag trainers (the Minouras, as an example) have optional rim drive. IMO, you're much better off getting a cheap rear wheel and a cheap, heavy tyre than you are using rim drives, but YMMV. There's less to go wrong with the trainer, and a cheapy wheel you can probably get for just about free.
What about rollers? You can't do (not easily anyway and I certainly wouldn't recommend it) hard intervals on rollers. They don't offer sufficient resistance, and you have to concentrate a lot on balance. They're worth having as well as a spinner, but not instead of (IMO anyway). Great for smooth pedaling and balance, but not for hard interval work.
Personally, if I didn't have the desire to splash out for a fluid-2, or some other brand of fluid trainer, I'd get a wind trainer and turn the stereo up louder, and use a wheel just for the spinner with a heavy rim and tyre. The heavy rim & tyre combo works like a flywheel and smooths out the resistance you're riding against a little, so it's more like riding your bike, where your momentum smooths things out A comparo of the Cyclops Fluid 2 and the Kurt Kinetic Road Machine is here.
Finally, it's worth getting a bike-bra, or some other sweat catcher, when you're using an indoor trainer, you will get very hot, and will drip sweat everywhere. Protecting your bike from corrosive salty water is worth doing!
At the end of all this, the really important thing about spin trainers is having a plan for a session, and doing it. Just 'riding a trainer' will send you mad with boredom.