I've got one of each.
Certainly, alder is the brightest of the three, makes for a good lead guitar since it naturally produces a more 'cutting' tone. Alder is found in guitars like Jackson soloists.
Basswood (dispite the name) is not far off alder in terms of tonality. It is bright but with a more balanced midrange. You'll find most RGs are made from basswood.
Some people don't like these woods because they describe them as 'thin' sounding - which they can be.
In that case, mahogany produces a thicker tone with more lower frequencies to give it warmth. You'll often find
mahogany guitars have a maple top on them (a brighter wood) to balance out the tones. A prime example of a typically mahogany guitar is a
les paul. Sabres are also usually mahogany.
