I need to "fetch" my UML skills and I'm looking to some good tools.
I thank Francesco for the following links:
MagicDraw seems to be better than Rational Rose.
The community edition hasn't reverse engineering or code generation support and it's limited to 20 shapes for diagrams (...but It's good for me, I've just to draw some architectures and explain them).
StarUml is veeeery young but it's growing I'l take a look on it.
ArgoUML I worked and love it and in the past but now it's no more updated. I think that Poseidon is the commercial version of ArgoUML.