I'm a newbie exerciser too. Well, new since I haven't exercised consistently in the past 2 or 3 years, anyway.
Right now, I'm just leisurely exercising. I'm very out of shape, I can walk a mile or two but not fast. The thought of doing aerobics, man, I would just fall over in a heap on the floor at this stage.

I'm starting on my exercise bike, watching Tivo'ed stuff on TV. And I don't push myself hard. I work up a very light sweat, and I'm never panting. I do get a little winded, though.
It sort of doesn't feel like exercise, in that I'm not out there fully exerted myself. But if I did that, I'd fall over after the first day and never do it again. I figure 30 minutes of low-intensity 'workouts' to start with has got to be better than sitting on the couch, and if it's not the best I could be doing, oh well. I still feel a little guilty, though. Like I'm not exercising right, like I should be pushing myself so hard that I can't do more than talk between pants. But, eh. That's not what I want right now. Hard enough to get in 30 minutes 5 or 6 days a week, I don't want more stress on doing it.