I use different RAW files at different exposures... I think it comes out better than a single raw file. My camera can autobracket exposures, so I set that up, put it in continuous shoot mode on Av (so it keeps the same F stop and only changes the shutter speed). Here are the originals:
After you blend them together in Photomatix, run a tone mapping on then to get the final image.
I uploaded the images so if anyone is interested they can try a "practice" HDR with the free version of Photomatix or Photoshop or whatever....