Well, you want a reputation as a "go-to" person. The ability to get your fingers into all kinds of pies can be pretty interesting (as in: when layoffs have happened, you are more likely to survive because you can work on anything).

Some organizations don't like this. They want to pigeon-hole you as "the mouse driver guy" or whatever, and when your company stops making mice you're in trouble. Avoid these places if you can.