Basic items as starting point :
12GB 3 channel DDR3 1600MHz CL7 G.Skill
Gigabyte GA-EX58-UD3R X58
ATI FireGL V7700 (non gaming) or HD5850 (gaming)
Intel SSDs 80GB
Samsung F3 1TB
You have probably already : Monitor, keyboard, mouse, speakers, x64 OS.
For the softwares..I leave this for someone else to answer.
next time read first :http://www.tomshardware.co.uk/forum/261222-13-build-advice