the only real difference is the superdrive. do you need dvd burning? do you want it? if so, go for the 2.16 ghz. otherwise, save some dough and get the 2.0 ghz.
You won't notice a speed difference between the two unless you normally use VERY processor intensive applications. The real difference is the Superdrive only being in the higher end one.
I had this dilema, the question is:
is an extra 7% speed, DVD burner and extra 40Gb HD worth £130?
Personally, I'll don't need that extra 7% speed. I dont need to burn DVDs and I'm probbaly going to buy an external HD in the future or replace the internal HD with a bigger one anyway.
I'm putting the £130 toward a nice big external monitor.
You get a larger hard drive and superdrive. For the $200 difference both upgrades were worth it for me, since I would have had to upgrade both those things myself and would have cost me almost the same. Plus you get a tiny speed bump which really isn't even noticeable.