I use the Planet Waves NS Capo. The G7 capo is probably very good but checking it out on eBay its very expensive!! The NS capo is light, nifty and can be operated with one hand. (I do it with one hand!). For me the Shub is a good second option.
The capo useum is fascinating. Its amazing how many different ways guitarists over the centuries have devised of improvising such a device.
http://www.sternercapo.se/Capomuseum/. If you ever get washed up on a desert island pencil and a rubber band also works!