Corsair just makes awesome everything. With that said...
- CPU: ($200) i5-2500k.
- Mobo: ($150) Any Z68 from a major maker like Asus, Gigabyte, MSI, etc...
- GPU: ($250) GTX 570 or 2GB HD 6950.
- RAM: ($30) Any 4x2GB DDR3 RAM will work.
- SSD: ($120) For the OS and some games/programs.
- HDD: ($75) 2TB HDD for everything else.
- Case: ($60) Antec 300
- PSU: ($80) Anything Corsair or Seasonic around 600W
Overclock : You can bring an i5-2500k from 3.3ghz to 4.5ghz pretty easily. But you'll have to invest an extra $25-$60 for a good cooler. I suggest the ($60) Corsair H60. But you can get by with some cheaper ones.
And as far your budget goes, if you remove the SSD you'll be near $800, but for general everything use, a SSD is the biggest gain in performance you'll see. I hate using computers without SSDs now. Even the extra split second it takes to load simple programs like Firefox annoys me.