I use the hoods all the time, they almost never come off the lens once I get it out of the box. They help protect the lens as well as control flare.
re: 90mm ... I've often thought about one of the newer 90mm lenses, then I pull out my M-Rokkor 90mm f/4 (mine is an early production, so identical to the Elmar-C 90 other than the bezel) and realize it's still a fantastic lens. If I were to buy a newer 90mm, I'd go for the Macro-Elmar-M 90mm f/4 kit: having the close up capability would be nice.