My wife and I are going to be taking a lot of driving trips soon, including a cross country one, so I'm looking to purchase a GPS, but I don't want to spend a forture. Ideally I'd like to keep it under $400. I don't see any units in that price range that have text-to-speech though. For GPS owners with text-to-speech, do you feel that is a must have? If you don't have a unit with text-to-speech do you find it somewhat difficult to follow the directions without looking at the screen for street names, or is "Turn left in 200 feet" good enough?