You've been here since 2008 and have somehow missed all the discussions about trainers?
I use a fluid trainer. I have tried a magnetic trainer, a wind trainer, and an old fashioned style of trainer which holds the bicycle at both front and back wheel. I like the fluid trainer the best.
See examples of fluid trainers here:
http://www.nashbar.com/bikes/SubCate..._202335_202382
Yes, it holds my bicycle just fine. I also use a riser block to hold my front wheel, but in the absence of a riser block, I have used a phone book.
You don't ride at the same resistance all the time. You can still shift gears like you do when riding outside, or you can snug or loosen the device that rests against the rear wheel as desired.
And, of course, you can do different things with your trainer. When I've used a trainer (a lot, some winters) I've usually varied between:
a) commercial intervals: 30-60 minutes on the bicycle while watching a good show on TV, on a station with commercials. I ride at a more relaxed pace through the show, and ride as hard as I can through the commercial, then recover during the show, and "sprint" through the commercial, and repeat. 30-60 minutes passes in no time.
b) endurance rides: 60+ minutes while watching a good movie, either on TV or rented ... something fascinating that will keep me interested and pedalling relatively briskly.