D40, D50, Cannon, Refurbished?

I'm looking to get a DSLR and I've been looking at the Nikons. I mainly shoot outdoor stuff, wildlife, maybe low light stuff. I'm wondering if Any of these cameras would better than the other at this.

Also, I'm seeing some pretty good deals on refurbished cameras that come with 90 Nikon warranty's. Anybody with any experience with them? I would think that 90 would be long enough.

If it helps, I'm looking at a D50

The D50 is an excellent camera. I wouldn't hesitate to buy a refurb. Just make sure you by one from an authorized dealer. I know Cameta had some good prices on D50 refurb kits. I would probably pick up a Mack Extended Warranty with it just so you're fully covered.