Our back yard now features a wooden play structure. Like, with two swings and a slide and a raised fort and a spot for a sandbox underneath the fort. (See the SC-F2 here.) It's a bit excessive, but Emma really likes swings and slides, and having them nearby makes Melissa's day much easier.
The playset has two swings: one baby swing and one belt swing (the kind you're used to). I expected the belt swing to go unused for a few years, but soon after we got it, Melissa told me that swinging alongside Emma is great stress relief. I thought she was being silly, but I tried it. It's embarassingly theraputic. Once I'm swinging, it's all I can do to resist going high and jumping off, but that would set a bad example for impressionable young Emma. Must resist.