I run mine at 37-38F, (I like em cold). My dad heats up a glass with hot water before pouring a beer from my taps, then lets it sit for a while after he pulls a pint, (he likes em warm).
I think it's all personal preference, just adjust your CO2 pressure if you adjust your kegerator temp.
it really depends what type of beer you serve. normally darker beers are served warmer (up to 55 F). I run my keezer at 38 and just let the stouts warm up a little bit
I got the bright idea of measuring the temp of my bottled beer. I drink my beer around 52F. Might seem hot, but 52F is pretty cold when it 111F outside.
I just need to figure out the keg pressure for 48F now.