CrossFilters down in Florida has been supplying most of my filter needs, they stock a few different brands. I've been mostly using Donaldson, Fleetguard, Baldwin and HiFlo filters. I like the slightly better water rejection of the Baldwin water separator for my AirDog lift pump. Wix makes most of the air filters and the OEM's and auto parts stores just relabel the suckers. Genos Garage is great for Cummins/Ram supplies, not the cheapest, but very good quality name brand stuff, quick shipping. I got an Edge CTS3 gauge system from them next day here in Alabama. Being so close is nice, the FedEx Ground is like overnight air service here.
With the price difference I only shop at the local Oreilly's when I get in a bind, the Wix filters cost twice as much locally and then there is our 10% sales tax. I save lots of money avoiding the local auto parts stores for filters!