A good set of keys should have several qualities: they should be easy to carry, not redundant, and fit your daily tasks. The last two can take some time, but the ease of carry is a quick fix. If you like to hook your keys to your belt, something like the hook from Scout up above is perfect, and it, like most keychain tools, doubles as a bottle opener. There are also tools like the Griffin Multitool that has a slough of tools with a belt hoop built in-- because everything should do more than one thing, right?. I actually keep the Griffin apart from my keys and use it as an alternative to a pocket knife when I travel and don't check a bag, for which it is perfect.