DR KAY:Why does he need a sub, surely the floorstander's would produce enough bass or is it that a sub goes more deeper and add's more scale compared with the bass that the floorstander's will produce.
Correct, there are no floorstanders in this price range that will get anywhere near a sub for depth and scale.
Also is it crucial to have a sub in a 5.1 system or can you get away with just the floorstander's, rear speaker's and centre speaker when watching movie's or would i be missing out on something special.
Hell, you can get away with anything, I don't have a sub and I'm using standmounts! But then I've never had one, so I don't know what I'm missing. I'm well aware the system struggles at the bottom end though and you have to be careful with the settings on your other speakers. I blew the baffle on one of my rears across the room once because I had them set to Large and there was a particularly loud (and sudden) bang in one the scenes in Terminator 2!