JoelF, if your kitchen is pretty cool and you keep the cooker closed, I'd say you could go quite a while (did you read Blood, Bones & Butter, where she talked in the last part about her mother-in-law keeping everything at room temperature for days on end?). Myself, I'll go for two days, and if it's not gone, it gets tossed into a batch of muffins or the next loaf of bread. But generally, with this crowd, it vanishes before I even get a scoop myself, sometimes.
When I do get some (and it's always the steel-cut oats), I don't get very adventurous: a pat of butter, a spoon of brown sugar, and a splash of cream. Sometimes toasted pecan or almonds, a handful of fresh berries, or apples and cinnamon (mixed in for the last ten minutes of cooking).
I love using the rice cooker. The one from Costco lets me set it up overnight... the only glitch is that the oats seem to bubble up and really muck up the vent. Is it just because I'm doing double batches? (see above re: living with a ravening horde). I wonder if there's something I could put in there to reduce the surface tension of the bubbles or something...
“Assuredly it is a great accomplishment to be a novelist, but it is no mediocre glory to be a cook.” -- Alexandre Dumas
"I give you Chicago. It is no London and Harvard. It is not Paris and buttermilk. It is American in every chitling and sparerib. It is alive from tail to snout." -- H.L. Mencken