What home fitness equipment offers the best results?
I want to purchase a single piece of workout equipment that offers aerobic activity but will also tone muscle. I want to burn fat and calories and tone my muscles without bulking up.

I have been running on a treadmill in our apartment complex gym, and love the results. But I was wondering if something like an elliptical machine would offer the same results or better without the wear and tear on my body caused by running?

All you need are dumbbells. Use light dumbbells to make the treadmill harder. You can also do high intensity interval training like that. Then with heavier dumbbells you can do a full body basic weight lifting routine a couple times a week to tone your muscles. Don't worry, you can't bulk up without steroids. You will gain some muscle, but you won't look big at all. It will also help you gain bone density and keep your joints healthy. This will help you avoid osteoperosis and stiff joints when you get older.

I do like elipticals. I do my intervals on those. You just switch between a high and low setting. Why not get get both. Adjustable dumbbells are cheap anyway.