I like grain. Grain can be good. Grain can also be bad. Just like everything else.

Honestly, I cringe when I hear people refer to anything having to do with photography in terms of right, wrong, good, or bad. IMO anything can be right, wrong, good, or bad, depending on how it is used. If I'm doing a newborn shoot, with their blotchy skin and hairy backs, I'm probably going to go for grainless and smooth out the textures -- it contributes to the softness of the subject matter.

On the other hand, when I'm shooting kids jumping on a bed with a photojournalistic approach, grain can contribute greatly to the feel I'm looking for. I just did a fashion session in which I photographed a male underwear model in the bathroom of a dilapidated building. The shots were gritty by nature, and I used Tri-X pushed to 6400 to increase that effect.