Go with the P67 version. Unless you're using an SSD too small to hold your OS or absolutely need Quicksync, you're wasting your money going with Z68. It absolutely gives you no advantage over the earlier chipset, especially gaming wise.
Even if saving money isn't your game, you should go with the P67 deluxe. Its a better board for overclocking, the dual LAN is particularly nice: I go ISP -> Mobo -> Router, and the front panel USB 3 hub is really nice.
This chipset variant, which was available alongside H67 at the launch of the Sandy Bridge platform, does not support the use of integrated graphics – but in trade supports the ability to run two dedicated video cards (for Crossfire or SLI, if motherboard manufacturers license those technologies). It also is capable of being overclocked, and that combination of features have made it popular for gamers and other demanding users.
The Z68 chipset is a late arrival, but combines the performance-oriented features of P67 with the onboard graphics options of H67. This opens up the option for enthusiasts who want to have a powerful video card while also being able to access features of the on-chip Intel HD graphics, like Quick Sync, without needing multiple monitors. However, using both of those together requires third-party software from LucidLogix – which isn’t ideal, as it means depending on yet another layer of complication in order to access all the features of the hardware. Quick Sync in particular is also only supported by a few video transcoding programs, so unless you use software that is designed to work with it then there would be no need for Z68 over P67.