I bought the HC3000 last month. Overall I'm quite happy (after some much needed calibration that my 4805 never required). Color temperature out of the box is pretty far off, but can be dialed in nicely with a little patience. But this is also true of the HD1000 from what I've read.
I too was pondering whether to get the 3000 or 1000 and ultimately decided that I wanted better black levels rather than more brightness. The HC3000 is quite bright (a bit brighter than my 4805 was) but the HD1000 is even brighter (due to the white segment). Also, the iris on the 3000 really helps with smaller screens and brings black levels down as low as I've ever seen on a digital projector. Shadow detail is excellent and the image really pops.
Unless you want to project onto a very large screen (over 133") I would recommend the HC3000 for a dark home theatre. Yeah, it's a bit more money, but it's still a tremendous value.
One caveat, there is speculation that Mitsubishi may be waiting to clear the US supply channels and then may release the HC3100 and HC1100 here. The 3100 would probably be priced the same as the HD73 and the 1100 would be around the current price of the 3000. It's a rumor, but since the HC3000 is discontinued, there is an obvious hole in the US product line so I tend to believe it.
[Edited by ctcushing on Feb 21, 2007 at 9:40 AM]