I'm with Gato on this one. I would've picked George, but I've only seen part of the one he's in. It's very easy to ignore the fact that he ever played Bond. Moore, on the other hand, was Bond for far too long. I'll just ditto everything Gato said about him. I suppose we could blame a lot of it on the writers. The puerile humor really took over the series while Roger was there. I liked Timothy a lot because when he came on board they decided to make the series a little more grown up.
I would rate them this way:
1. Sean Connery
2. Pierce Brosnan
3. Timothy Dalton
4. George Lazenby
10. Roger Moore