[Halcyon]

First thing, never buy your interconnects from Comet.
That's like saying you'l buy a computer from PC World.
You will pay more.

Secondly, is it worth it ?
Well it is worth it if you have the money to go all the way.
If you spend a tonne of money on the DVD Audio player and then buy a reasonably priced Amp and speakers, then there is absolutely no point.
If you put money in one part, you have to put it in the other.
Cabling can make a lot of difference as you can sometimes loose treble and bass through cheaper cables.
So make sure you go for good quality speaker cable but also good quality interconnects from amp to CD / DVD player.

Then there is also the positioning of speakers and the size of room to consider but thats another thing to delve into some other time.