In answer to gaffbass, I have a petersen strobe tuner, which i use at home, and it is super accurate, but to be honest, too accurate for stage use, it is a super fine tuner, I use it for setting up intonation on my basses at home, and nothing is better.
For stage use i use the planet waves pedal tuner, brilliant, dead simple to use and effective, basically checking my tuning every third or so song. or after a particularly energetic number, slap etc, it takes seconds and can be done whilst singer is doing the chat, I cannot imagine not user a tuner live. Our guitarist uses his me50 too, there is nothing worse than being out of tune live.