I use Northern Brewer/Briess extract exclusively. It's always very fresh, and produces excellent beers.
As far as recipe kits go, I've tried a few Northern Brewer kits and they were great. My brother-in-law brews a lot of Austin Home Brew kits and loves them. I tried two of the beers that he brewed from AHB kits (Sam Smith Oatmeal Stout clone and a double IPA), and they were awesome.