Do-it-yourself compenent system vs. surround sound KIT

How many of you have a surround sound system made up of a component stereo system? Is this a better option than a KIT system? Currently I have:

8" powered subwoofer (I want a 12" or 15")
2 bookshelf speakers with 8" woofers
2 floor-standing speakers with dual 8" woofers.

I think that it is always better to use a real surround sound receiver and big speakers than the el cheapo surround sound kits. All I need now is a basic 5.1 channel receiver and a center channel.

How does this look?

http://www.newegg.com/Product/Produc...82E16882105282

http://www.newegg.com/Product/Produc...82E16882290022

http://www.amazon.com/Sony-SA-W3000-...0046518&sr=1-7

Because come tax time I plan on upgrading my Pc anyways and if I want to enjoy playing games I want to finally have a surround system. And since I have a majority of the components already, Why not put then to actual use?

Now, my next question is how would this setup compare to a top-of-the-line kit?

This one here, one of the most expensive, looks like the speakers would be incomparable to even the most basic of floor-standing speakers. I assume the stereo imaging would be better because of the speakers being matched, but how does sound quality compare?

http://www.newegg.com/Product/Produc...82E16836121120