I have a D3000. Its' main shortcoming as far as I'm concerned is that it is quite noisy at high ISO, but that said I took
this picture recently and it looks great at medium size. You can only really see the noise when you view it at 100% size on a monitor, which is way bigger than you'd ever print it anyway. You can get round the problem by setting the auto ISO to not go above 800 as it's above 800 that it starts to get particularly bad.
Other than that it's great, it can be a bit slow to process images when you fill the buffer with ADL on, but then again I very rarely actually shoot six-frame bursts so it doesn't matter to me. I do like the look of the D7000 as a potential upgrade in the future because it's got more direct access controls for quicker changing of settings etc but if you get the D3000 as a first SLR you won't be disappointed.
When Ren Rockwell says it's Nikon's worst ever DSLR don't forget that he's comparing it to pro bodies that cost over ten times as much.