In many ways she is a very good choice. By incorporating her into his administration Obama is healing the rift that they may have created in the democratic party during their primary battle. Furthermore she has extensive contacts with foreign leaders and strong knowledge of foreign governments and foreign affairs.
What remains to be seen is whether Clinton will follow Obama's agenda or her own. How well will these two work together? She gives every indication of being more hawkish than Obama. And we don't need hawks anymore! Nevertheless, I'm in a state of guarded optimism. There is every chance this will turn out to be a very successful move.
We shall wait and see . . . .