Zooms make me lazy, especially at the wide to short telephoto range. I'd much rather use 20mm, 50mm and 85mm primes with a single long zoom than have just two zooms. Currently I have the Sigma EX 10-20mm to give me wide-angle on the D70s (effectively 15-30mm) but I don't enjoy it. Maybe if I tape up the zoom ring so it is effectively a fixed 20mm equiv ...
I still find it hard to go out with only ones lens and hate having to change too often so it does discipline me into roughly planning the shots I want to get. Ad astra per aspera