Have you considered the p67 chipset?
Most of the boards have had all their bugs revised out and, if you don't need the extra features on the z68, the p67 is great value.
The 2500k/2600k has a proven track record on these boards and there are a lot of forum members using these setups so there is a glut of advice/experience if you run into problems. Plus a an 'almost' guaranteed hassle free clock of ~4.5GHz.
Having said that if the AMD route fulfills your criteria stick with that - i'm only offering an alterntive to the z68 i'm not suggesting that AMD is a poor choice...