I'm sure I would like the stair climber, but the only time I tried it back when I was 14 or 15 I think I had a hard time not falling off. Ellipticals are ok, but they just feel to awkward to me. They do give you a good workout though.
Running, biking, and jump roping is where I'm at right now. But my knees are not to fond of the jogging, might need some new shoes...
If you don't mind me asking, what kind of shoes are you running in right now?
They're Nike Dual Fusion, I think. They worked fine last year but they're past there prime now. I'm flat footed too so my knees have always given me some issues.