The one that you employ your knowledge got by hard study. I like Powdercell because it is free and simple. There are private ones that supposely do everthing. But you still need study to use them.

You can even use python or matlib for most of the problems, the important is to know what you are looking for and the theories behind it.

Check with this two software will help you,

X'Pert HighScore and OriginPro8 where you can find all kind of analysis and measurements like full-width half-maximum, peak positions, etc

Have you tried the 'R' programming suite?