Is This The Best Possible Budget Build for $2700

[brob]

But it's just light rendering with Sony Vegas. Nothing bigger than 720 or 1080

 

It's up to you how fast you want renders done. In my experience Sony Vegas does not make good use of gpu for acceleration so cpu become more important. Rendering wise, the only real difference between an i5-4690K, i7-4690K, i7-6700, or i7-5820 is how fast they are going to get the job done. Given the budget, any of these cpu works. So it boils down to sub 1:1 render times vs 2 or 3:1, i.e. one vs two or three minutes to render 1 minute of video.