I thought this would be a nifty idea; a spot to recommend books, DVD's etc on Bellydance!
My contributions; there's one called Luscious which is very low impact, pretty long (about 2 hours) but covers a lot in that time, and it's really good for an introduction to bellydance. It's also go a workout part towards the end (about half an hour) so you don't have to go through the introductions to the different steps every single time; you can just skip that lot and do the dance.
For something more advanced or intensive, I recommend Rania; I have found a box-set on Amazon for less than ten bucks which includes bellydance boogie, cardio shimmy, hip-hop hip-drop and pure sweat. As well as being a good cardio workout, the steps are slightly more advanced without being impossible, and they demonstrate well the different types of music you can dance to (i.e. Hip-hop hip-drop is done to hip-hop and club music, pure sweat is done to Latin, etc.)