Dr Hiran Krauss:
The one thing I stick do is some DM advice I heard from Chris Perkins DM to the celebrities that you should run with whatever sounds cool to you now not save it for the future. So I tend to just throw out whatever peaks my interest during that day week or month depending on the situation.
The only problem with that advice is that if I followed it, you guys would now be swarmed by about 50 different types of enemies. (Some of which are designed to be majorly difficult to defeat.) Not only that, but about 50 other people would show up offering for you guys to hire them. Oh, and magic items would basically be raining from the sky...
All that would be fun, but really difficult to write. :-P