Beginning Audio System

Heya, i've decided that I want to start building my first Hi-Fi audio system. The problem is that I really don't know where to start or what most things are. Things like "pre-amp" and "tube" dont really make much sense to me yet :(
What i'm really after is an Amp with 5.1, probally no more than 60watts, a CD and SACD player, two good speakers for stereo music, a subwoofer and two more speakers to work with the good speakers for when I listen to surround sound. I don't think i'm going to have enough money for the two surround speakers to be of highest quality. I'll porbally connect everything with optical wiring aswel.
My budget is about £500 .. could someone point me in the right direction and explain what the different speaker types and amps are?
Thanks alot
Tom