As obvious as it sounds, I strongly recommend shopping at a specialty bike store. They are the experts, and they will be able to help you decide which bike is best for you.
There are signs that the age of petroleum has passed its zenith. Adjusted for inflation, a barrel of crude oil now sells for three times its long-run average. The large western oil companies, which cartellised the industry for much of the 20th century, are now selling more oil than they find, and are thus in the throes of liquidation.