If you're a computer nerd with his own computer in his own room then there's no reason to order the PC grow kit.
If you have some spare wire, a cheap soldering iron, a handful bright blue and another handful of bright red LEDs, and a spare parallel port cable you can pretty much turn your working computer into a grow box. You don't have to worry about raising the power bill or setting up ventilation... you'd be killing two birds with one stone: functional computer + grow box.
If you really wanted to, you can just strap some charcoal filter to the exhaust fan from the inside to eliminate odours. In the case that some smell still leaks out, and you're a weirdo that likes to burn incense, then strap a charcoal filter to the intake fan of your computer and burn some cannabis incense. If anyone asks, just say the smell from the incense lingers.
...and if you're really tech savvy, you can program your grow box to automatically control the lighting and, if you want, hook up a webcam inside the comp so you can watch without even opening the box.