Oh, one more thing: I finally getting comfortable enough with my understanding of the Bitcoin system to start considering building a "real" mining rig, so I started looking at the logistics.
I found a calculator which seems to be quite all-encompassing at https://bitclockers.com/calc .
But unfortunately, I've come away a bit discouraged.
I wasn't aware of the impending mining "award" drop, though I've since read up on it on the wiki. I was going to start off buying a single 7970 and dropping it into a repurposed box that would do the job nicely. However, with the costs of energy ($.09/kwh, it looks like, though I still need to verify it with my service), it looks like I'd be barely breaking even once the reward drops. Is that an experience that's not unusual, or am I missing something? The 7970 is listed there at 350 watts and 600 Mh/s (though most people on here are reporting around 700Mh/s with the 7970, and so is the number I've been using). Is 350 watts correct for that card?
Based on that particular page, it seems I'd be better off (though less scalable for growth) if I got two 6950s instead, since I'd end up with a slightly better hash rate and slightly lower power usage, at around the same cost of entry. But even still, I'd be looking at under 5 dollars a week of profit, and take 2 1/2 years to "break even". It seems odd that there doesn't seem to be a card out there that can give any better return than that.
Can anyone shed a bit of brief guidence on this subject?
Thanks!