15 feet of tubing should be plenty for any build, especially in a micro atx space. D5 and DDC pumps are pretty popular, but theres a lot to choose from.
http://www.frozencpu.com/cat/l2/g30/c107/list/p1/Liquid_Cooling-PC_Water_Cooling_Pumps.html
just to give you something to peruse...
also with that much stuff to restrict your flow, it would not be a bad idea to have 2 pumps in series not only for better flow but also redundancy if one fails. you'll likely be fine with just one though. or you could make 2 seperate loops. one for the cpu, one for the gpus. but im guessing space is going to be your biggest issue in a micro atx case.
you're also going to need a reservoir, fittings, blocks, etc. i would also suggest getting what you need to have a drain port at a low point in the system.
to start getting an idea of how things are down, i suggest looking up jaystwocents on youtube. his watercooling videos are what gave me the confidence to try it for myself.
http://www.overclock.net/t/1415725/a-guide-to-water-cooling-multiple-gpus
and i'll leave that if you want to get a lot more in detail.