Yes i would spend the extra money and get a two day pass.
Friday will be less crowded, great time to hit up Diamondback, Firehawk ( tends to be a long line as well) and maybe Flight of Fear. If you like great wooden coasters ride The Racer and The Beast ( 30th birthday this year. so give it some love). you should also check out the Son of Beast if you like rough woodies.
Drop Tower is very fun as well.
I would start out on friday and ride the Diamondback first... Ride whatever else sounds fun, but when it gets dark go and ride The Beast. It is awesome in the dark since it is in the woods. Son of Beast isnt bad either at night.
Hope this helps!!