Honestly, I think you really need to ask yourself if you NEED a notebook PC... If you need a PC to take to school or on trips and that ALSO will play games, that's one thing- I have a Dell Latitude D600 from work that's not quite as nice as the laptop you're looking at, and I play City of Heroes/Villains (with faiurly minimal graphics, true) and Guild Wars on it when I travel and it's acceptible. Not half as nice or fast as my desktop (an aging AMD 2100+ system) but it gets the job done. Top-end games like F.E.A.R will likely choke it, though if you use any sort of antialiasing or anisotropic filtering.
I have no idea why you'd need something fancy like a wireless mouse or anything like that- I just use a cheap-o USB mico-mouse (a free gift at a trade show) and it works great. Networking should be on the mobo. A USB hard drive is a nice add-on for moving files back and forth, and is not too expensive (just buy a 3.5" HDD and an external case kit for $30).
Really, the only challenge I have is HEAT- my Dell pumps out a LOT of heat when I play, so much so that it will really warm up your legs if you use it in your lap. Use a lap desk or other insulated, hard surface that won't restrict crucial air-flow (or sear your family jewels).
If you don't necessarily need a notebook for school/work, I'd spend the same money on a desktop- you'll get faster componants for the money, it's upgradable more easily down the line, and is still portable enough to take to LAN parties and such...
