Re: the post credits stuff, They are probably testing the waters and gauging reactions on that, I didn't see the scene myself but I manged to get up to speed on youtube.
I recall Favrau mentioning these things tend to lose momentum after 2 movies and was planning on maybe doing 2 iron man films and then a 3rd with a larger scope - ie: Iron man and the Avengers, or whatever.
At least he doesnt want to make sequels just for the sake of sequels / cash. looked what happened to batman circa Joel Schumacher
Iirc, They were also planning to not have Obi be the villain until the second film. I guess we'll see how things play out now...Given Iron Man 2 already has a release date [April 30, 2010]