On Thursday
HTC has already announced its super phone, the HTC One, which has gotten decent reviews. It should be out in the next month.
Until Samsung's phone is official, you should hold off on your Android phone purchase.
You'll want to see what Samsung is offering, and how prices are going to adjust.
You might even want to hold off on an iPhone purchase unless you totally hate Android. In which case, go nuts buying an iPhone (or Windows Phone or Blackberry.)