Chris Reeve Knives. I had a few very, very small rust spots on my Sebenza's blade and was told to send it in to see what they could do. Two weeks later, my knife came back with a brand new blade at no charge.
Kind of off topic, but SureFire also has excellent customer service. Like an idiot, I didn't lock out the tail cap when I threw my 6P into my backpack and the tail switch kept the light on long enough to melt the lens. I called SureFire, told them what I did, and they asked me for my address and said a new replacement lens is on it's way.
Also, the people over at Plaza Cutlery (a knife shop here in SoCal/Orange County) are awesome. Everybody there is friendly, knowledgable, and very helpful. When I asked to see one knife, I was shown that one and a few others that were similar. The person behind the counter also explained stuff about each knife he brought down from the wall and out from the display case.
[rant mode on] However, on the complete opposite end of the spectrum is a store called "Turner's Outdoorsman." The one in Irvine really pissed me off. I was in there looking at some SureFires and when I asked to see one of them, the person who opened up the display case pretty much ignored my questions and talked to his friend instead. I bought the light anyway and the old lady behind the counter was nice enough. Well, I brought it home and realized it wasn't what I expected the more I held it. So the next day, I took it back for a return and that same old hag behind the counter gave me attitude for returning it. Apparently, they have a 30 day return policy, but will piss and moan if you want them to honor it. Complete bullshit if you ask me. Thinking it was an isolated incident, I went back a few months later to purchase another SureFire for a present and the same thing happened when I asked a few questions. I fired off an e-mail to the president of the company and the PR department and never got a reply. Wonderful company, eh?
Now, I tell everybody not to go to Turners even if the other stores aren't like the one I went to. I'd rather spend a litle more money elsewhere and be treated like a customer rather than an inconvenience. [/rant mode off]