I find riding a trainer or a gym spin bike very boring. I've done a couple of spin classes with a very good cyclist as the lead and it was intense but my schedule was such that I couldn't do it regularly.
When my career dictated a lot of time in hotels I discovered two devices I like OK.
The first is sort of a spin bike but a little different. I'm not sure what the resistance comes from in a Lifecycle but it's fairly well modulated.
You can select a program from a menu of a variety of intensities and types. There are warm up and cool down cycles built into the programs. What I like about this machine is the display shows the up coming effort or the relief. It really can simulate a good workout on a hilly road. There is a HRM built in to many of the models. You can also manually program a work out.
I also like a Concept II rowing machine. Very smooth action and a full body work out. The monitor shows your level of intensity, "distance" rowed and a HRM can be attached to many monitors.
And like the oilman noted, a member of the opposite sex as a workout partner helps with, ahh, motivation.