The guy who sold me the bike told me he would switch between the 3 main types of gas you get at the pump. He said he usually used the cheapest gas, but sometimes would "treat" the bike with the most expensive one (I don't know the numbers).

I'm not really into switching gas as I don't think it's good for the engine. What do you think? Which gas do you usually use? The cheapest or the most expensive one?

Thanks

Cheapo regular. Works just fine for me.

I JUST found a place that has signs on the pumps saying
      "No Ethanol"

Thats where Ill be going for mine. Their El Cheapo is only about 2 cents more than the Ethanol crap..

Well it seems that most of you run on cheapo. Good to know. I shall do that too from now on.
Thank you

Although Suzuki calls for regular, in the past some members have said they use premium because of the need for higher octane due to pre-ignition.  The Suzuki is an air cooled engine which runs hot in heavy traffic conditions or prolonged idling, especially in SoCal, where you live.  This causes the internal cylinder temp to rise, which can cause pre-ignition.  As long as you do not have mechanical issues, Hi-Octane gas takes care of that problem, in the Suzuki.  I lived in SoCal myself and had the problem on hot days, and in the desert, until I switched to premium.

Also, the difference in costs from one brand to another is largely determined by its additive package.  Considering how cheap it is to gas up your bike, why not spend the few extra pennies to buy gas with a really good additive package?

High octane gasoline is not "better" than low octane.  It is better at preventing detonation, pre-ignition, ping, spark knock, whatever you want to call the explosion inside the combustion chamber instead of the controlled burn we should have.

As Gort said, use 87 when cool and 91 or 92 when very hot.  There is no point using mid-octane gasoline.

Stimpy kind'a has things backwards.  Lower octane is OK at high altitude in engines without knock sensors, thus the availability of 85 octane in the Rocky Mountain areas with less dense air containing less oxygen.  (For more advanced engines than our Suzukis, use the octane level recommended in your owner's manual.  All automobile engines after 1986 are more advanced than our bike engines!)

Better brands of gasoline do have better additive packages for competitive reasons.  The EPA establishes minimums, but some gasoline marketers exceed these minimum standards.
http://www.toptiergas.com/.  
Here on the West Coast BP's ARCO brand has the worst gas I've found.  The gas mileage in my car & truck with ARCO are noticeably worse than with any other brand including no-name supermarket gasoline (Which is often Tesoro here).

I have it backwards, really?  (thanx 4 clearing it up for me).

It's just that my bike ran beautifully at sea level w/regular
and not so much here at 6,500 feet.

------

Ummm, no. "Petrol" is just the brit word for gasoline,
cause the stuff is made from "petroleum" you know, that nasty
black shi* that our lords and masters pump up from the ground

 I generally use the higher octane because my father has always told me too. However I have realized over the years that father isn't always right hehe. Old school dies hard. I have been having issues with my bike and I may switch to the 87 to see how it goes for a while.
 I'm curious how some of you decide which stations or fuel producers to use and which not to use. Do you just look up the companies online and see what additives they use or do you generally just go from personal experience with each tank or series of tank fill ups?
 Also I love in Indiana where it's not generally too hot or too cold. I also realize some states have different additive packages. Anyone out there live in Indiana that has a preference for a particular brand and the reasons you use it?

Thanks