I don't think banana plugs are essential, but when I got my 14 gauge wire they made the setup easier and 'cleaner'.
If you have a MicroCenter (microcenter.com) in your area, I picked up the banana plugs for $0.97 a piece -- they look and work just like the ones on monoprice. I'm really glad I got them, but I don't know if I would've ordered them specially unless they came at the same time as everything else.
Enjoy your new setup -- I bet you'll enjoy it a lot as an upgrade to your current setup!!