Some of that really depends on the problem and the language. I program Java full time, yet I'd be useless with vi. I lean heavily on the IDE. I've done this a long time and I firmly believe that I should use the best tools available, not just a text editor or a TEXTAREA, even with syntax highlighting.

Having suffered through a couple code interviews in Java, I now pick Python when allowed to pick a language. It seems like the language for me that allows me the best chance of coding effectively without an IDE.

I just did a phone screen yesterday that was extremely painful. After 45 minutes of fumbling around the thing mercifully ended and I googled for a few solutions. According to what I read on stack overflow, the problem is unsolvable with the constraints given. I expect to get the "no thanks" email from the recruiter soon and I plan on asking him what the proposed solution to the problem was - not out of spite, but because I'm genuinely curious. Maybe I misunderstood the problem statement.