Speaker Systems and DVD usage on ps 2

[Geoduck]

I'll be purchasing a set of speakers for my ps 1+2 consoles within this month.

But something's puzzling me regarding the speaker systems I see on sale at the shops. Most of the packages include an amplifier and a set of front speakers (some more expensive ones include rear speakers).

What about the receiver?

I thought that speakers need a receiver to process the data from the game-console/tv/dvd-player and distribute it to the speakers, while an amplifier just... amplifies.

I know next to nothing about speakers, so the bottom line is, what do I need for a complete (functional, at least) external audio system:

a) receiver+speakers

b) amplifier+speakers

c) receiver+amplifier+speakers

Also, what kind of "sold-separately" wires would I need? And if I were to hook my ps 1, ps 2, and vcd player to the speaker system, would I need a lot of those wires? More importantly, CAN the system accomodate so many sources at the same time?

I feel like a monkey in the pilot's seat of a helicopter