Hi sotypical!
For cardio, I do the elliptical, the crossramp, the stepmill, and the treadmill (not all on the same day, that would be a lot of cardio

). On the treadmill and the stepmill, I do intervals. On the crossramp, I do a fifteen min workout, change the incline every 2.5 min, and go backwards for 2.5 min. On the elliptical, I'm boring. I don't know why I don't mix it up there, but I just get on that thing and go at the same pace and same resistance for 15 min.
I also like spinning. If your gym offers spinning classes, I encourage you to check one out, since you like the stationary bike. Spinning is like the recumbent bike on steroids. I've heard that it is one of the highest calorie burning exercises you can do.
Doing intervals on the stepmill definitely gets my heart rate up. It always says the calories I've burned are low compared to the other machines, but I think it's because the stepmill is older. I think either it or the other machines are just wrong (I know, it's probably the other machines that are too high). I know my heart rate is getting up there, so I'm confident it's burning a comparable amount of calories as the other machines.
I'd also encourage you to check out some classes. You might be able to find some classes that use free weights, which would help you get started with them.
And, if you can afford a trainer, I'd go for it instead of waiting. I've had a trainer for going on three years now and it was the smartest decision I ever made. I've definitely progressed a lot faster than I would have if I was exercising on my own. In fact, if I didn't have my trainer, I'm pretty sure I would have quit going to the gym after a couple of months. I was totally lost when it came to the weight machines and free weights; having a trainer has really helped my confidence. It's really hard to learn proper form from a book, and proper form is really important if you are using free weights. Having a trainer is really helpful in that respect, as well.
When I do cardio, I listen to my iPod. It's made a huge improvement in my workouts. I have a special playlist of favorite songs that I only listen to when I exercise. It helps me look forward to my cardio workouts. I don't try to read. If I'm able to read while doing cardio, that's a sign that I'm not working hard enough.
I started to see very modest results after a month or so. I didn't actually lose weight right way because in the beginning I was just working out with my trainier three days a week. I didn't do any cardio on my own and didn't change my diet at all. But even with that limited amount of exercise, I noticed that my clothes were starting to fit a little better after a month or so. At that point I added some cardio on my own and also began restricting my calories. Once I did that, I started losing weight pretty consistently.