I had been wrestling with a noisy chain for a long time. I'd messed with chain tension and chainline and chain lube, nothing really worked for any long period of time.
Anyway, I hadn't lubed my chain in a while, so one morning as I was about to leave for work, I picked up the bottle of lube that my dad uses (ahem, on his bike) and doused my chain in it. It was Finish Line ("all-weather" or something like that) as opposed to the White Lightning that I was using at the shop. Holy Moses! My bike is silent. No squeaks, but even more surprising, no clicking, no "roller-coaster-starting-up-the-hill" noises. Even back-pedaling, which usually made everything louder, is silent.
The Finish Line lube that I used is a real thick lube, almost like Phil's Tenacious Oil, as opposed to White Lightning which is mostly (i think) alcohol, mixed with solids, which gives it that "cleaning" feature.
So all this got me thinking. On a geared bike, you want to avoid over-lubing -- it just attracts lots of gunk. But on a SS or fixie, why is that a problem? Sure, a dirty drivetrain takes away some efficiency, but if it really gets to be a problem I can buy a new chain and clean the cog and chainring for oh, $15.
I'd much rather have wonderful silence due to a gunky chain than that bit of efficiency.