Hardware recommendations?

Hey guys, I've been out of the game for about four years (U.S. Navy) and I want to build a new computer. I am very computer literate. Due to my amount of time gone, I don't really know what is common place for hardware these days. I have a $700-$750 budget to build the whole computer- monitor not included. It would help a lot for you guys to give me some recommendations. Thanks.