Budget Range: about 20 000 CZK, that is about 1 000 USD, but would rather keep it under 900 USD because HW is a bit more expensive in Czech Republic
System Usage from Most to Least Important: Gaming, school stuff(office applications et c.), Internet browsing ... Gaming, everything else is secondary
Parts Not Required: Input/output devices (headphones, microphone, monitor, mouse keyboard et c.)
Preferred Website(s) for Parts: gonna buy from a brick & mortar shop, just use newegg/ whatever you think will work for reference; maybe you can use a Czech e-shop like czechcomputer.cz(http://bit.ly/eUEAzU; note that the English translation sucks, but I think you can get your head around it) or alza.cz(use google translator if you want)
Country of Origin: I am from Czech Rep.
Parts Preferences: need a Wireless LAN(Wi-Fi) card
Overclocking: Could be, but I want high reliability.
SLI or Crossfire: Can be, but I do not want to expand our electricity bill for no reason.
Monitor Resolution: 1680x1050
Additional Comments: Wi-Fi card(as I mentioned), screw-less case(screw-less opening, HDD in/uninstallment) reliability, low upkeep et c. Just a good gaming PC with a Wi-Fi card(preferably with decent Linux drivers).