1. Firstly your not going to buy a 100 pound sound card for a shit piece of speakers such as the Logitech X-530 Multimedia Speakers 5.1. If you were to buy the Logitech Z-5500 THX Certified 5.1 Speaker System then yeah why not.
2. Just proved your are clueless about gamers. So you are saying this "Logitech Cordless Desktop Bluetooth MX 5500 with LASER Optical Mouse" is better than a G15 keyboard and G500. Gamers don't want wireless stuff it's slow and give's you headaches when there are too many around. Plus G15 is all about macro keys which you need in games such as World of Warcraft or any other MMORPG, strategy game.
3.That power supply is a newer model than the one you suggested, and why would you buy a 1000watt PSU for a single slot GPU 480 GTX. An 850watt corsair or lets say 750Watt one is more than enough.
4.Why would you need a network card? The Asus Rampage III Extreme which again is a newer model than the one I suggested includes 2 ethernet ports.
5. The monitor I suggested gives a higher contrast ratio.
6. Of course I did but asking for 1000 euro just to setup a PC that requires only 1 hour of setup is a lot.
I have built 4 rigs on my own took me 1 hour to put the parts together and a day on stress testing the pc for BSOD errors. At the end of the day everything worked perfect.
Only downside about building a PC is getting faulty hardware which is a pain in the butt to go through the RMA process.