For ordinary printed images, I'd have no problem at any setting, I've printed some up to ISO 102000 and they look sharp clear and no visible noise printed at 8.5 X 11.
Looking at Raws with no NR at 100%, you definitely notice noise creeping in at ISO 3200, but its generally not a issue even at 6400 as long as you have a perfect exposure. Underexpose at high ISO's and it falls apart.
With Lightroom 4, there is no more fill light, which is a good thing. You can be much more precise about pulling up dark areas with the new controls.