i think the reason most people think taller, not wider is better is the fact it's getting quite hard to get the wider tyre's for the smaller size rims like the 14/15 inch ones. and since the focus on aftermarket rims is bigger is better, tyre companies are following suit. for example, it'd actually cost me more to buy a set of 265/60/15's than 265/40/17's for the vc. being $285ea and $230ea respectively.
now i actually prefer the smaller rims on the old girls, but the way it seems things are heading i'm going to have to buy a bigger set of rims just to be able to buy a competitively priced tyre