Ah, co-sleepers. Everyone said we have to have one, so we rushed out to purchase an Arms Reach in the days leading up to our daughter's birth. It was a folding plastic and metal thing, and it was supposedly portable and good for traveling with baby -- but only (we discovered) if you really like to sherpa. So once she was done with it (and they grow out of them fast!) it was folded up for the one trip it has since made: into storage.
Considering all the room the thing took up and its short time in the field (our daughter preferred to sleep in a crib at 3 weeks), we might have done better with a rented or purchased Baby Bunk. Made of solid wood (which feels so much warmer and fuzzier), this mom-designed bassinet attaches to the side of your bed like a conventional co-sleeper, and has almost a Shaker look to it. We like that they're rentable, but there's an incentive to buy one: it converts into a child-size bench once your baby's toddling. Baby Bunks can be rented for $30/month and purchased for $265 - $295.