I chose the D40 partly because it's among the very quietest DSLRs out there -- which is great for candid indoor people shots. The meter and focussing work in quite low light. The menus and shooting menu are well thought out, for the most part. 6 megapickles is plenty of res for me. I like that the many custom settings let me set the camera up for my shooting prefs.
Why do I say the meter is out to lunch? Well, it's not, if you're an innocent, average consumer looking to make family snaps. This camera will keep your kids and pets looking bright, colourful and punchy. But it's so intent on working its magic on stuff in the centre/bottom of the frame, that it's content to sometimes gleefully clip all highlights, and other times to underexpose and totally waste the top 1/4 of the available dynamic range. Center-weighted is a bit more predictable than matrix, but I still have to always check the histogram, and 4 out 5 times need to compensate. (By the way, don't trust the standard, mono histogram, which is based on the green channel only; always check the RGB one via Retouch>Filter Effects>Color Balance.)
I like a lot about Nikon ergonomics. But I regret that twirling the rear command dial requires that your thumb gives up its grip on the back of the camera.
So that makes one major caveat, and one very minor one. Other then those: I like everything else. Now that I'm getting quicker at compensating for the meter, I'm starting to get more consistent results, and it's becoming fun.
Check "that mega auction site" for demo bodies at a fantastic price; I only paid $290 (July 08). Oh, and check kenrockwell.com for lots of D40 user tips.