you need a minimum temperature of 225 in order to get that rich, savory taste and color that come from browning. there's something magical that happens to meat at those temperatures and i am sure there is some science to explain it, but i prefer to think of it is "getting good."
in my smoking experience, i've found my best cooking temperatures to be in the 240-250 range. even if it gets up to 275 for a few minutes (i use a charcoal smoker) i don't worry too much about it.
bottom line: "low and slow" can be taken too far.
one caveat: if cold smoking some meats, scuh as sausage, smoked fish etc., you want temperatures even lower than 215. 180 degrees, if i rememebr correctly, is more appropriate for these types of specialties. for cheese, you want to go lower still - try to keep your temps below 90 degrees. other than that, shoot for something between 225 and 250 and you will enjoy your meat much more.
[edit] as dude said, for poultry you want to go even higher - the reason for this is that poultry is already tender and does not require "low-n-slow...."
