I worked out for many years at local gyms. There's nothing like the convenience of all the various machines to alleviate the repeated setup hassle. That's what many of these all-in-one machines suffer from.
In any case, after leaving the gym scene I used one simple and inexpensive piece of equipment to keep myself in very good shape....a $29 adjustable chin-up bar. It came with mounts for the top of the door frame as well as for the bottom (for sit ups etc). The number of exercises one can manage is quite sufficient to get/keep in shape. Add a jump rope and you have your cardio workout as well.
$17.99 shipped
http://www.amazon.com/GoFit-GF-CUB-Chin-Up-Bar/dp/B0007W2FLI