I was reading that the switch to generating 25 BTC at a time instead of 50 will happen very soon.
Even then, if you were only earning $7/day with a single 5970 rig, the payback period is not that long. It seems obviously worth doing, unless you think there will be a run on Bitcoin within the next 6 months or that a sudden move to ASIC will make GPU mining obsolete. I think I'm going to go for it. I might even take the risky investment and hold my bitcoins.
The switch to 25 BTC will happen at block 210,000, which will happen in January 2012. https://en.bitcoin.it/wiki/File:Total_bitcoins_over_time_gra...
Just like how GPU mining made CPU mining unprofitable, something else could come along and make GPU mining unprofitable. Probably couldn't happen before you've gotten your hardware purchase paid off though. Of course, if the exchange rate drops significantly, like the scenario pointed out here: ( http://mtgox.com/blog/?p=262 ) and doesn't recover for a while, you could end up never covering the cost of the equipment for your rig.
I was reading that the switch to generating 25 BTC at a time instead of 50 will happen very soon.
Even then, if you were only earning $7/day with a single 5970 rig, the payback period is not that long. It seems obviously worth doing, unless you think there will be a run on Bitcoin within the next 6 months or that a sudden move to ASIC will make GPU mining obsolete. I think I'm going to go for it. I might even take the risky investment and hold my bitcoins.