Fortunately Google Instant has Google Classic built in. You just have to type in a search term and then hit RETURN. I use it this way most of the time out of habit.
Personally I think Google Instant is great, and this guy's design suggestions for making it more readable pretty much gut it.
It would be Google Classic if the bottom half of the screen would stop changing as I'm typing. Right now, I hate using Google proper... it hurts my eyes. Then again, I pretty much just use the location bar in Chrome to do Google searches, so I'm not affected much, but Instant is a big difference over Classic.
Personally I think Google Instant is great, and this guy's design suggestions for making it more readable pretty much gut it.
But hey, I'm an engineer, so I like efficiency.