I use a trainer a LOT. In fact, in the fall/winter, pretty much 100% of my miles are on the trainer. I vastly prefer riding outdoors, and would give my left nut to do so more, but life and nature simply makes it impossible for me during this time of year.

I'm pretty "die-hard" on mental toughness - I'll crank out workouts at 4AM (even 3AM) if I have to, and I've run 20+ miles on a treadmill, with weeks on end of 90+ minute sessions with zero music, zero entertainment.

Still, riding a trainer with no stimulus is mind-numbingly boring. It'll literally kill you and any passion you have to get out and keep doing it over and over, which is the whole point. Anybody can do a week of hardcore trainer work, but to do it for months on end requires more than a hardcore mindset. I can't last more than 3 sessions in a row on it without my "setup."

Now though, I really enjoy my trainer sessions. In fact, I think if it weren't for the lack of group riding with friends and competitive others, I actually enjoy the workout part of it more than being on the road, since it's so efficient and so consistent. (I very well may find a way to suck some of my friends into doing these with me on a semiregular basis.)

The keys for me:
- Good training DVD or video. The two sets I use are Spinervals and Sufferfest. Sufferfest is an online download for $11, and is completely worth it - the music tracks alone are outstanding and would cost nearly the entire DVD if purchased separately. Spinervals is sold on DVDs, costs $25ish each, and are videos of a coached gym class, which means the scenery is of other cyclists suffering on the trainer like you are. Spinervals though benefits from having Coach Troy yelling into your ear the entire workout, which is surprisingly motivating, as most of the interval sets are hard enough so that I have a hard time even looking up at the computer screen. I've got about 10 total, and by rotating them, it's a great mix. I'd start with Sufferfest, as it's cheap as heck to buy, and every bit as quality a workout, with much better music - the whole set is completely worth it.

- Speed/cadence computer, and preferably HRM. (Powermeter is best, though!) You seriously need some sort of feedback on the trainer, or it's death. The speed sensor serves as a "poor man's powermeter" and is very accurate for comparing your efforts between workouts. You work harder, you go faster. Slack off, and speed drops. After you do enough workouts, if you can download them (Garmin), you can actually get a good sense of how fit you are for road riding by comparing your tempo efforts/HR for trainer and road sessions done days apart. I know if I can hammer one of the Spinervals DVDs at a certain speed/HR, I can hammer most of a hilly 50 mile loop here fast enough to keep up with the local roadie crew.

- Good workout space. Having to setup and break down your bike and computer/DVD every time you use the trainer will kill your already low motivation to ride on it. Clear out a good permanent space for it (at least for the season you're using it). Most folks have found that a 20 foot headphone extension cord (can get at Radio Shack) works better than wireless headphones if you want pumping music without deafening the place. Having a good trainer is also a given (KK or Cycleops Fluid). I just have my trainer/bike in my garage, and it doesn't look like an inviting space at all, but it's great for working out - I can sweat buckets and not worry about damaging the floor or disturbing the family.

I ride pretty hard on the trainer - usually hard enough that I can't even watch an action DVD because it's too distracting from focusing on my workout. As a nonracer, you'll probably be able to enjoy movies (to some degree) on the trainer, but I'd still do dedicated workout videos regularly to keep yourself improving.