Not a fan of ethanol. It's efficient burn ratio is around 9:1 (9 parts oxygen 1 part fuel), where as methanol is 14.7:1. Most newer cars oxygen sensors will pick this up and start throwing more fuel into the engine and decreasing the gas mileage that you get. Although it isn't bad to run sometimes because it does clean the tank out a bit it seems (But it still uses a mixture that can be bad for seals, normally only in older cars though). I am, however, a fan of E85 if you're set up for it, but that's for different reasons.
As far as my opinion on the OPs topic. I always put higher octane in my gas engines before I go tow anything of a decent weight simply because even though it may be a hp/tq loss, you figure you're putting more stress on the engine anyway, causing it to heat up more. When this happens, you will be more prone to detonation and a higher octane rating could help save your internals in this case. All higher octane is, is a slower, more controlled burn which is why higher compression and higher power trucks/cars use it. It's less likely to ignite prematurely (which is what detonation is, there is another form of detonation but we wont get into that).
However, as far as daily driving and normal highway driving, I always recommend the lowest octane that your engine can handle for peak power and mileage. So higher octane will by no means hurt your engine, but if you use it correctly, it can really help. Just remember, the lower the octane, the faster the burn, the more power you get as long as you're avoiding detonation.
If you wanna know a little trick I use when I'm on the road, if you ever encounter detonation due to bad fuel, I would recommend staying away from the "octane boosters" in auto stores, head to a chemical or paint store and pick up either Toulene or Xylene. Toulene is rated at 114 octane and Xylene is rated at 117.
Here's the breakdown if you mix with Toulene.
Mixtures with 92 Octane Premium
Which is decent compared to the "boosters" you get at the auto store which are normally rated for 2-3 points (so those only increase your octane to about 92.3 total, per $5 bottle when you can buy a gallon of Toulene for around $3 a gallon!).
But anyway, if you're interested in that stuff here's a link.