GPUs for mining

Hello all, i am really liking the alt coin mining thing, but my old laptop, can not do it because of overheating. So i come home in 11 days on leave from deployment, and want to build a rig, and then bring it back with me to run (can you say free power)

So i would like to know what should be the main things to get, like Mother board, and cpu, ram soforth, power supply

as for the GPUs them selves i think AMD is the one to go with after reading everything, and dont mind spending a little

is the R9 290X the best option? or do i have better choices?

also not really sure how many cards i would want, but would like to keep the rig looking clean, maybe 2 or 3 cards if they fit

thanks for any help

Flexgroo

also might be a dumb questions, but how does running 2 or 3 or 10 cgminers on different pools affect your cards, hashrate and such