Ouch! Yeah, I've decided to go for the Pro as it's clear the Air, though it will still be capable enough for most users, isn't really designed for what I need it to do.
Surprised the fan would come on when just browsing the web and using a word processor though? What's activity monitor saying as surely there shouldn't be any load on it with just those apps running?
For anyone trying to decide whether to get the Macbook Air or the Macbook Pro this video does a good job of highlighting the differences and recommending which model would suit your needs.