If you're looking for a convenient way to charge a couple of Xbox 360 wireless controls at the same time, the Xbox 360 Energizer Power & Play Charging System is a reasonable option--though it's not the only one.
The Mad Catz Xbox 360 HDMI Conversion Kit delivers exactly what it promises--but you should only get it if you're looking to reduce cable clutter.
The Charge Base 360 works as advertised, but its bulky size and controller docking requirement make it a tough sell versus Microsoft's more compact alternative.
While we wished it cost a bit less, the Konnet PS3 and Xbox 360 Power Pyramid is a solid gaming accessory that will appeal to dual-console owners.
The Pelican Xbox 360 Fan Stand is a great cooling device, though we suspect the space you have to devote to using it is doing most of the work.