During coding interviews, I'm looking for the following evidence in a candidate:

1. how good is the candidate at problem solving?

2. is the candidate able to think in code?

3. are there any glaring syntax errors?

To assess the above three, a whiteboard, paper or Google Docs is sufficient. I'm not averse to using an IDE, just that the IDE's syntax checking hints will shift the candidate's focus to writing syntactically accurate code (#3) rather than on the problem (#1 and #2).