Over time I have been experimenting with using both ISO800 and ISO1600 when imaging.  So far I haven't been able to decide which I prefer.

The noise level of 1600 is easily manageable on cold nights (not as much so during the warm summer nights).

1600 obviously has the potential of cutting down on exposure time.  My ever-present tracking issues make the idea of shorter exposure times very appealing, but I'm wondering what the trade offs are for this.  Is there a reduction in potential well depth at the higher gain level?  My limited understanding of CCD technology makes me think that ISO800 will probably offer a better dynamic range.  Also, 1600 seems to exaggerate light pollution issues.

I'm wondering what other DSLR photographers are using and why.

Read the reply by Jay ballauer in this thread discussion for a more detailed explanation on your questions.
http://cs.astronomy.com/asycs/forums/p/35652/393154.aspx

i think 1600 ISO if you DONT have a choice because of guiding errors, if you dont have that problem, i wouldnt even consider it- 800 would be much better if you can track the exposure time