What type of bike are you considering?
For a proper fitting road bike you might need to go custom. Stop by a decent LBS, or several, and see what sizes they recommend for you.
Going by pants inseam is not accurate enough. Actual crotch bone to floor measurement in bare feet is generally what is wanted. Torso and arm lengths are also involved in a proper bike fitting.
Lots of info available if you Google "Bike Fit". Mostly drop bar road bike oriented.
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Gear Hubs Owned: Rohloff disc brake, SRAM iM9 disc brake, SRAM P5 freewheel, Sachs Torpedo 3 speed freewheel, NuVinci CVT, Shimano Alfine SG S-501, Sturmey Archer S5-2 Alloy. Other: 83 Colnago Super Record, Univega Via De Oro
Visit and join the Yahoo Geared Hub Bikes group for support and links.
http://groups.yahoo.com/group/Geared_hub_bikes/