Nikon, ever since my first FM2n, Titanium Shutter. That was my first "real" camera - purchased brand new on the recommendation of Terry Ernst, owner of Ernst Camera Shoppe in Port Huron, MI. He is still in business, still processing film for me. This carried over into my dSLRs as well. I do consider getting a K1000 every so often, some good friends of mine had these way back when and really liked them.
It is amazing how your first purchase can so influence your subsequent purchases, even if you didn't accumulate an extensive accessory collection. Always been happy with Nikon SLRs, never found a reason to consider others.