battery life depends on usage. If you are constantly fast forwarding/skipping songs you will drain the battery even if it's just music. Apple claims for 30GB drives up to 14 hours, 60GB 20 hours. So it should be at or a little less than that with general usage.
EDIT: As for the battery before recharging, it doesn't really matter that much. Cycles aren't determined by the number of charges but the number of fully completed cycles of charging of the battery. Advice on what's the best to do varies, I generally let it go down about 3/4 the way before recharging.
That's about what I do too. I never get even close to 14 hours on a charge though. Hmm. I do skip songs quite often, but.. do most of you really get close to 14 hours of use before having to recharge?
Well with my 30GB iPod it took the battery down to 50% after 1 lost episode, so at max what they claim... I would probably get another battery, I got a BTI battery i (70-80 hours audio on 3G) and watched about 8 hours of video without it dropping below 100%, i'd recommend them highly for video...