I asked a series of questions on iRosetta about the proper use of "etc." in writing. It is very often used in the wrong way.
1. "Comma before etc.?" and "Comma before etc., part two". Yes, there should be a comma before etc. when used in a list. See also this English Language and Usage question (a Stack Exchange 2.0 site).
2. "Is it always “etc.”?". Yes, etc. never loses its full stop.
3. "Mixed double punctuation -or beating a dead horse". About etc. as the last word before the ending punctuation, in particular a question mark. etc. does not lose its full stop in this case either.
4. "Law, etc. revisited". Use in a particular law text. Bad use is copied over and over in the law field.