Ethanol won't hurt it at all (unless you fill your tank with it and let it sit several months without driving... even then it will probably be okay). I do fill up with straight gas (no EtOH) when I know my car will be sitting for more than a couple of weeks, just in case.
Lowest octane without pinging/predetonation will give you the most power and fuel economy. We have 100% gas 87, E10 89 and E10 in the 90s where I live. I haven't noticed ANY difference between the straight gas and E10 as far as ill effects, power, or fuel economy. Might get a little less MPG on the ethanol, but it's cheaper per gallon to make up for it.
The biggest difference you'll see from gas is getting it fresh from a place that keeps their gas clean and dry. Sometimes this is big chains, but somtimes it's the little mom & pop places - depends on where you live. Also don't fill up if the station has been filled recently. It stirs up any water and sediments that might be in there. This will keep your pump, filters and injectors clean.
Edit: "EtOH" means ethanol. Habit from being in chemistry I guess
[This message has been edited by FieroGT42 (edited 07-06-2011).]
