I built a home gym a few years ago. Started with a good quality squat rack that can double for all the big core exercises. Added a treadmill a year or so later and some additional accessories. It's been such a wonderful investment for me because I don't have to leave the house to workout and I can always squeeze in some exercise around the busy schedule of work and family.

I especially love the treadmill because I can jump on it at the end of a long day and do an hour walk while watching TV and it really relaxes the mind and helps me get some light cardio while loosening my body.