I find loopers lots of fun, and certain ones do different things better then others. For example for looping bass I like the ditto looper because its simple and it doesn't suck tone. I have a digitech jamman looper that I use for sampling. It has built in memory so I record to it and use it to trigger samples live. Mostly things like audio clips from movies, sound effects, instruments that we can't cover (for example a keyboard part, as we don't want keyboard in every song so we don't need a dedicated keyboardists. For the jamman I just run it into a cheap IMP DI and out to FOH so its not in my bass signal chain at all.
