Got slashdotted yesterday, as you might know. Server didn't have any problems but i burned around 1,5 Gig of bandwith in one day on an otherwise low-traffic site. The automatic bandwith limit cut me off quite quickly, so my host added some more.
Here's what it looked like in bandwith terms - don't bother looking at the hours as i don't really know which timezone they belong to.
It looks like bandwith was cut twice. The first time, i had exceeded my quota by 50% so my host tripled the quota and promised to keep an eye on it. I guess the triple wasn't enough, as later i went out for lunch and it seems i met the tripled quota as well and the host raised it yet again.
Observation 1: Slashdotting hits instantly at peak - no build up, so there's no time for taking precautions
Observation 2: A good hosts is a good thing to have.