I have been playing around with Lightroom 4 and it has a great feature of converting NEF files to a compressed DNG.
I've experimented briefly with it, for example a 10mb NEF from a D3s it compresses anywhere between 4mb though to 9.6mb.
Viewing the jpegs produced up to pixel level I cannot see any difference at all. Maybe this can vary depending on detail or someone with a better eye? Also the jpegs produced by both come out pretty much the same size.
For the D800 and its large files this may be a great way of dealing with it if, like myself you shoot thousands of pics in a days work.
You could have a workflow of backing up all NEF files to archive. Then go through your initial culling and at the same time mark which you would like to work on as NEF (if worried about possible quality loss on your favs, ones that may need cropping or possible for enlargement) and then convert the rest to compressed DNG format.
This would save massive amounts of space, especially for high volume shooters. Yes...I know hard drives are cheap, but when you shoot thousands of frames a day and then look at 2 external backups it will be pretty expensive on the long run.
Any thoughts on the disadvantages of this? I'm not technical but so far only really see the benefits.