Well, whenever these discussions emerge, I try to inject some numbers to dampen down the "feelings" factor. So, here is a little Excel spreadsheet that will yield RPM's vs MPH for all gear, tire size and sprocket ratios. The spreadsheet depends on a thing called "rolling distance" which is the distance that your bike rolls for one revolution of the rear tire. It's a very simply concept, and is akin to the effective circumference of the tire. The operative word there is "effective" because there is no way to calculate or measure the "effective" circumference of a motorcycle tire due to its circular cross section. You have to actually move the bike forward for one revolution of the rear tire and then measure the distance that the bike moved.
The chart does, however, have two typical rolling distances shown, one for 18" tires and one for 16" tires so you can use these numbers to get a fairly accurate display of all the other numbers.
The rolling distance and sprocket teeth are pull downs that will give you a choice of values. Just choose whatever value you want and the RPM's and MPH for all gears will be calculated and displayed.
http://www.amckayltd.com/xs650revs.xls
The problem with this chart is that it introduces facts into an otherwise emotional discussion. People want to talk about how much better there bike "feels" with an 18 tooth front sprocket, or how the vibes are less because the RPMs are way lower, like, 3500 at 65 MPH, but if they were to figure out their rolling distance and plug the numbers into this spreadsheet, they may find that the RPMs are more like 4200 and the reason they are claiming 3500 is because their tach or speedo isn't working right, but, like any good story, we don't want facts to get in the way of the punch line!!
So, just figure out your rolling distance, plug the numbers into the chart and see for yourself what the numbers really are.....you can still lie about them if you want to!