So I will have a shiny 3x HD7970 rig, churning out 2GH/s - and my ASIC will eventually arrive, so I'll do ok in the long run.
I wouldn't be so sure about that, the total hashrate and difficulty will go up so fast will all these new ASIC's hitting the market that you will feel forced to invest more and more into mining equipment. It's a king of the hill battle with a neverending slope upwards and no top. Good luck with that, only the ones somewhere high up the hill will be able to make a good profit.
There were people back in 2011 saying mining was a waste, it was too late, you'd make more buying BTC. Mining is still quite profitable. I wouldn't hesitate to get into mining, it's not quite as insanely profitable as it used to be, but you'll make money. GPU I'd only do a few rigs that you can use as gaming rigs, the rest into ASIC. Plus it's fun and the more miners the better for the network (more decentralized, which is good).
The 7970s are fine cards, easy to resell if he can get more ASICs down the road.
That's why I am getting them. I will sell 2 of the 7970's when my first ASIC is shipped, then I will buy a 50GH/s ASIC, and just run that.
It will be good for a while, and I should have made enough to break even, with sufficient stored to get the upgrade when they are built - especially if the BTC keeps going up in value.