My windows home server 2011 build does all of those things very well. Lots of linux distributions that'll do the job well too if you're comfortable with them. If you're talking hardware requirements, I'd recommend minimum quad core processor with ~8Gb RAM. Most modern boards by Gigabyte, Asus, etc.. would be fine. With servers, always give yourself plenty of room to grow, A fast network and an excellent power supply. You're building for reliability.. not so much raw speed.