I prefer to have hand straps on my cameras, and have never had a good solution for my 20D until this:www.camdapter.com
I have tried the Canon battery grip + Canon E-1 hand strap, and don't like it at all. It doubles the size of the camera just so I can have a hand strap!
I've also tried a thing made by Hakuba, and it sucked. It was plastic, and too flexible, and blocked the battery door. (And it wasn't a tripod mount)
The guy who makes the Camdapters, Jim Garavuso, is a pleasure to deal with, and the adapter plates are exceptionally well-made. I would post pictures, but the shots on his website are better. You can roll over the pictures to see the other side.
I am using the double-ended Arca model, so I get a shoulder strap, a hand strap, and an arca plate all in one! It also keeps the bottom of my camera from getting dinged up when I set it down.
The hand straps he makes are also top-notch. They are a lot more comfortable than the Canon one. The E-1 from Canon stacks the nylon strap, so all the force is on a 1/2" strip on the back of your hand. The Camdapter strap has the nylon strap side-by-side, so the force is on a 1" wide strip.
I highly recommend the Camdapter + strap combo.
So, what was your favorite accessory of the year?
Disclaimer: I have no affiliation with the company or Jim, I'm just a really happy customer.