Quote from: SHlFT on July 30, 2011, 12:47:55 AM

And even more if the prices goes up.

That argument works both ways. But by the very nature of Bitcoin the price should certainly go up.

Quote from: nmat on July 30, 2011, 12:49:30 AM

In my humble opinion, anything that requires more than 2/3 months to pay the initial investment isn't not worth it. Difficulty is increasing which will extend those 8 months indefinitely.

Also: the 7000 series should be out soon and your hardware will become outdated.

PS: here's a calculator that estimates difficulty to help you with your choice: http://forum.bitcoin.org/index.php?topic=26751.0

That's what I was thinking. If it takes over 8 months to pay off then is it worth it. Considering when I do start taking profit it won't be much.
Maybe I should wait for the 7000 series, but to be honest they would have to use 50watts a piece to make them profitable in my part of the world.
If the hash rate increases it would just be cancelled out by a rise in difficulty due to blocks being completed quicker across the network.

So realistically, unless electric comes down in price or Bitcoins increase in value, this isn't a valid investment opportunity really is it?