So ISO 800 and 1600 is noisy? Noisy compared to what, specifically? My Nikon D50 produces lots of noise at ISO 800 and 1600 as well, but it's not a lot of noise if compared to film, and not compared to other DSLRs on the market.
My D50 is just as good as the Canon 350D at ISO 1600. I realize that this is the rare occasion where a Nikon matches up to a Canon in terms of (low) noise, but my point is that noise at ISO 800 and 1600 will always be present.
If you regularly print at 8x10" or larger, surely you're doing at least some post processing with your photos and using noise reduction software before printing them, right? Lets use software like Noise Ninja, for example. If you use Noise Ninja, you'll see that the noise levels of photos from Canon, Nikon, Olympus, and Pentax will all be comparable (if they aren't already similar anyway), because there is software on the market that is just that good.