I've ordered my first mb, a gigabyte ga-z68-d3-b3 for $80. This seemed the cheapest way for me to enter the z68 world. It is 16x pcie and 4x, so no sli. My thoughts are that in 2 years if I want to add a second gtx580 I will buy another mb that is 16x/16x but that will be standard at $100 mobo price point, and I will reap the benefits of 3.0 pcie, and other undiscovered goodies. Or just spend $120 now on a mb that is 16x/8x? Also, please clarify is sli an option on my current ga-z68-d3-b3? I can't find anything on this board b/c everybody thinks this is a cheap board.
x16/x4 isn't as bad as you think. It's just that you'll get more out of the x8/x8. If you do plan to sli gtx 580.. a good dual x16 motherboard ranges from $300-350. The gtx 580 is a beast of a card, I think you should just use it for now until ivy bridge comes out for a good amount of time. I think you can flash the bios of current 1155 to work with ivy bridge but you won't get some features. I'm also sure that nothing really saturates the pcie 2.0/2.1 slots atm.. so pcie 3.0 isn't that important. In other words, stick to what you have and see what the future brings you. You can rethink this when there's new and better technology out.