Important tip to all those who are ordering these bottles for the first time: READ THE INSTRUCTIONS!
I know that something as simple as a water bottle wouldn't make you instantly dive for the manual, but the Brita filters all needed to be primed by flushing one whole bottle of water through them before use (to get rid of loose dust inside the filter left over from its manufacture). If you didn't flush the filter first, the first couple of bottles would taste awful.
I figure the Culligan and Pur bottles probably need the same treatment, so it's a good idea to check the instructions before you actually use the bottles.