I used Performance Friction front brake pads on RLDSL's recommendation. I haven't towed with them yet, and I don't have them on the rears (not sure what brand's on the rear shoes), but they do seem to stop better than what I had previously. FWIW...
BTW, you probably know this already, but MAKE SURE you lubricate every sliding point on the shoes and on whatever the shoe rides on. The only two brake jobs I've ever needed to do on my truck were due to thing freezing up (a rear brake adjuster froze in 2005, and a caliper froze earlier this year)...