I very seldom use the standard (boring focal lengths of 28 to 75mm) - and prefer the more extreme focal lengths. I'm not too interested in how the specs look - more if I'm getting the quality image I'm after.
The two lengths I prefer are 20mm for wide angle and 180mm to 300mm for long focal lengths - especially for landscape, architectural and editorial work. My view is that I am using my wide angle for the effect of everything in focus - so close it right down to f22
(technically f16 would be better but a difference isn't noticable in my work). On the other end, the reason I'm using a long lens is to have the compression effect and shallow depth of field - plus I need all the shutter speed I can get to have sharp shots - so I almost always shoot wide open
, even with lenses that aren't optimized for it like my 75-210mm and 75 to 300mm zooms or my 300mm f4.5.
The only other focal length I use for candids and portraits is my 85mm 1.8 and I regularly shoot it wide open with fast film for natural light indoor shots and only close it down to f5.6 if I have a portrait of more than one person where DOF is more of an issue.
Experiment like mentioned above - you may well be satisfied with the results of closed right down for wide angle and open right up for teles - as I generally am.http://watcherreport.com/prophotoforum/