I have the Soma Deco, though I was looking for both style and substance. I am sure other posters will have additional recommendations too! It is great but I want a chrome rack because it will look nicer with my bike!

This one is good because you can strap on panniers. I have a bungee cord I use to attack my lock, and I have some pannier like baskets. I do think that racks with springs clips are more useful, but for me it is not a big deal because i also have a front basket. So anything I might have used with the spring goes in my front basket. a front basket is a must have for me, because I need a place for a purse.

But for me the list of must haves for a useful rack:
1. carrying load of at least 30 pounds
2. rails for panniers
3. loops for bungee cords to connect to securely
4. optional: spring clip

I plan to get this one, as it'll look nicer on my bike.

There are even less expensive ones that work well, depending on your needs. Or you can get a luxury Nitto rack. Lovely, but too pricey for me at the moment!