Toe-in will help minimize squealing and vibration related chatter and noises, but not grinding. If the brakes are properly adjusted and still making grinding noises it's probably time to try different pads.

Another advantage to some Kool Stops is the wedge or plow-tip shown in the pads above, and in their Eagle 2 pads for cantilever brakes. These take the guesswork out of toe-in. Just mash the pad flat against the rims, align them with the rim to avoid rubbing the tires, and cinch 'em down. The wedge sets the toe-in and helps scrape water and mud off the rims in messy conditions. I like the Eagle 2 pads so well for my mountain bike's canti brakes I'll get the thinline pads shown above for my hybrid's V-brakes next time I replace the pads -- probably in a few months at the current rate of wear.

The thinline pads made by Kool Stop and Jagwire are also easier to align on thin rims to avoid tire rub. The Eagle 2 pads are a bit wider than I'd like and a hassle to align optimally on the rear rim. I use Jagwire thinline pads on the front to provide more fork clearance when changing flats -- the Eagle 2 pads are much thicker and didn't provide enough fork clearance for easy tire repairs, although they worked just fine.