Fly, press, curl, and plyo bench for me, Jane Fonda--or whatever high-strung YouTube workout bunny took over for her--step aerobics for my girlfriend. If I could own only one piece of fitness equipment...well, I would pick a BOSU. But my second choice would be an adjustable bench. Body weight + a change in level = countless ways to work off the BBQ ribs, and make myself hungry again so I can eat more.
Reebok's Professional deck workout bench adds another layer to the traditional step with its hinged surface. In addition to movable legs that lift the bench from 8" to 14" (or slope it for use at an incline or decline) the Professional Deck has a "lid" on top that lifts and locks into 3 different positions for seated exercises with dumbbells and resistance tubes. It also has 4 pairs of attachment points to keep the latter stable and even during use.
Lifting the Deck's lid reveals a small storage compartment for additional fitness equipment, and maybe a few pick-me-up snacks in between sets.