So apparently there's several different Macbook's available.

I'm deciding between two at the moment. One is £120 more expensive and comes with 120GB hard drive instead of 80GB and an "8x double-layer Superdrive" instead of a "24x combodrive" + a 2.16 Ghz processor instead of a 2.0.

None of this means anything to me. Will it actually be worth paying the extra or not? I can't really afford to spend loads but, given I can't really afford what I'm gonna spend, I want to make sure I spend it on the best thing possible economically if that makes sense.