Onboard video will not be as fast as GT260. You could get by with a GT650 non-Ti though, which are really cheap and super low power.
Just get an AsRock Z87 mobo, no reason to go bananas with super pricey mobos. Asrock Z87 will do 16GB ram, have Gbit lan, and decent onboard sound, along with USB3, etc. The only reason for expensive Z87 boards is for people that need dual Gbit lan, more than 6 Sata ports, SLI/CF, and the like. You can also get more power phases, but to be honest, I haven't ANY OC difference between $300 Maximus Formula and $90 Micro Center Asrock Z87 with Haswell CPUs. One will stick at 4.5Ghz on the Asrock, then same 4.5Ghz on the Maximus. Ditto the average Haswell getting stuck at 4.2/4.3, the limit is actually the silicon and TIM dual lottery that those CPUs have. Besides, with Haswell, you get good enough performance without OC. Because they strip a bunch of features out of the K chips now, you will probably get the best professional app performance with a 4770 instead of 4670K/4770K. You also get the bonus of the non-K chip being a bit cheaper. Most people agree that overclocking business machines to be a non-starter anyway.