Best digital SLR for around $400?

I want something that also does video, quality video. Either Nikon or Cannon.

Not gonna happen

the cheapest DSLR with video is the Canon Rebel T3, which starts at $550 at pretty much all retailers
the next cheapest is the Nikon D3100 at $700 and the Canon Rebel T1i at $700

For that price, it'll have to be a used one. No new Canon DSLR is available with video at around $400.

The Nikon D3100 is available for $699.99 from Nikon's website. I found it IN my local Best Buy for $599.99.

No video at $400, not even at $500. Minimum $550 for Canon EOS T3.

At your level you have Canon EOS XS and Nikon D3000, both around $450.

Here's a DSLR Buying Guide - http://www.the-dslr-photographer.com/2009/11/which-dslr-to-buy/