LAN MAN: get small, get light

I have a desktop that I am quite pleased with. But while I started with a very light aluminum case (full-size), the beast got very heavy real quick after I installed everything. Three hard drives and two optical drives contribute to the weight.

So now my next project will be what I really was after all along, a LAN machine. With a stable desktop, I no longer really need to worry about back-up etc. So I want to build a mid... maybe even a micro ATX, with enough power for good grapics. FPS and RTS LAN experiences are the objective, with power, weight, and expense the primary concerns.

I won't be doing video.

I want one HD, one Optical drive, one graphics card, and air cool. And this stuff has to fit together d@mmit.  

With a little shopping I can probably find it all and at a decent price. But quick question: what format optical drive will I need?

And then what are your opinions of a build?

thanks!