I love my rain cape; previous comments about fenders being required for effective rain cape usage are correct. I have the Carradice Pro Route; it's got two internal cloth loops on the front that go over your thumbs, and another loop in the back that goes around your waist.

Here's a recent photo on a rainy day that stopped raining:


I like the ProRoute vs. the Duxback because it's so high-viz.
It's somewhere on the spectrum between UberGeek and PeterPan, but it's very effective and I love it.

This page contains pictures of a few different versions of bicycle rain capes.