CPU + Motherboard combo, worth it?

Yes this is a good deal and as future proof as it gets. If it is for gaming go for it!

Except for this being like $100 less at Micro Center there is nothing to say bad about this deal. Gigabyte is a great company and the 3570k is a great processor.

A 2600k would do fine too, but it depends on what you want to use it for. The 2500k and 3570k quad core processors with no HT are generally preferable for games because they are simpler and there is less in the way of OCing them, but audio/video programs benefit a whole lot from having the HT from the 2600k.