Everything looks good but I have a few suggestions though.
- If you were to use a GTX 670 instead of the 680 you would still get great 1080p performance at a better price.
- Personally I find the SP120 High Performance fans much too loud for the temps I get out of them. I would go with 2 Gentle Typhoon 1850's or if your ok with their interesting colour scheme 2 Noctua NF-F12's. If your fine with the extra noise have at it, I myself can't stand the amount of noise they make even with the low noise adapters
- I also suggest the Asus VH326H over the Dell's as depending on where you get them from, they are either cheaper or the same price + the Asus's have more connections then the Dell's.
Other then that you got a good build plan going.