I'm building my 1st Computer...
I bought an ASUS P8Z68 Deluxe and an Intel i5 2500k.
What would be the Best Video Graphic Card? I would Like to stay Under $150.

Tom's Hardware is one source for gaming hardware reviews and benchmarks. The site maintains an ongoing list of the Best Graphics Cards For The Money and is a good starting point for deciding which card offers the most bang for the buck for the specific games you play.