I started a Kettlebell regimen two weeks ago. I'm just doing it at home for 30 minutes at a pop, because that's all I have time for. I did it the first time just for grins with my wife's 7-pound kettlebell. She had never used it. Two days later, I was walking like an old man because of my quads being on fire.
So last week, I went and bought myself a 15-pound GoFit countour kettlebell. I would highly recommend them. They come with a 30-minute bodyshred Bob Harper workout. Bob is very good about showing you proper form and positioning before each "move". He has two 50-minute DVDs that have very good reviews. I'll probably get them in the future.
The GoFit Countour bells don't bang against your arms when doing presses, etc. And the grip feels good in your hand. I know you can get them in 7, 10, 15, 20, 25, 35 and 45 pound bells.