Let's face it, not everyone can afford an HP Blackbird 002, which was used for several MLG pro gaming tournaments and was awarded 4.5 stars (out of 5) by CNET. The Editors' bottom line at the time was "If you can afford it, and you want a high-end gaming PC, buy this one. End of story." The end of that story was a $5,600 hole in your wallet, which is not a very happy ending for most of us mortals (Wired gave its $2,100 successor, the HP Firebird, a 9 out of 10). The actual happy compromise is in your peripherals, which you can splurge on (within reason) without having to win the Lotto.
I'll start with the mouse. More than your keyboard, your mouse is your most important gaming peripheral. For laptop users, who will more often than not use the default keyboard built-in to their machine, dedicated gaming keyboards are a luxury rather than a necessity. Furthermore, PvP enthusiasts necessarily learn to move with a mouse, which makes it a worthy investment.