OK, after Yahooing my Sunday morning away reading about copper toxicity, etc here's what I've come up with.
You might develope vomiting, nausea, runs if you drink water that has been standing in a copper pipe for a while (overnight, etc). Flush the pipe for 15-30 seconds and the risk is virtually minimized.

Copper toxicity in cookware is indeed aggravated by acidic foods or if the pot has spots that have oxidized into a copper salt (that blue green crud). Symptoms are as above, short duration, and can may be mistakenly refered to as "stomach flu".

Since at least the fur trade era the majority of copper cookware has been tinned or lined with some other metal. Even top of the line chefware such as De Buyer or Maurviel (sp?) has a stainless lining. I guess it just wouldn't do to barf your expensive French dinner all over the maitre de on your way out the door <img src="images/graemlins/blush.gif" alt="" />

So, as long as you kettle hasn't oxidized, you're probably right, for a water boiler it's going to be a nonissue

http://www.atsdr.cdc.gov/toxprofiles/tp132.pdf has a 295 pages of information on the subject, from "does inhaling copper fumes cause impotence?" (they don't know <img src="images/graemlins/confused.gif" alt="" />) to "how much copper sulfate does it take to kill a hamster in 2 weeks?" (quite a bit <img src="images/graemlins/crazy.gif" alt="" />)

Ed