I'm keeping my 03 4.4 for a while. It's paid off and I hope to get another 5 or so years out of her (I keep em til they die). I don't like the e70 so that's not even a consideration for me, but the X6 may be at some point.

I was at a dealer the other day (for my 540) and asked one of the sales guys about a price drop of e53's, to my surprise he said they haven't really dropped like a lot of people expected and has been pretty stable. He said that a lot of people just don't like the e70 (sounds familiar) and even some of his typical 'new' car buyers are going used to get an e53. So the used e53 market is still strong.

My guess is that in addition to the people who just don't like the e70, there are other people who are just waiting for 2nd and 3rd production cycles or thinking about an X6 as the next logical alternative. If the e70 and X6 seem to be winners in the next couple years, I think more e53's will start flooding the marketplace and then prices will drop. However, you never know.