Why so high is because a miner in hand is worth a lot more than something on a slow boat from China. Also a private transaction sold to someone in the EU then you also avoid VAT by declaring it as a used computer. I know genesis block blah blah blah. Have you seen BTC prices? Currently $204 at MtGox. You will get your 30 BTC back in 60 days. At that point if a BTC is worth $400 then you got yourself a nice ROI. All about risk versus potential reward. The one thing genesis block can't predict and no one can is where BTC price will be in 60 days. You can only speculate.
In 60 days if BTC is at $400, then you should have held on to that BTC & you wouldn't be out the extra money from electricity, storage, etc.
You say that someone would get 30BTC back in 60 days... Let's assume I use the date of your post (the 22nd)... and the seller gets the 30BTC offer and miraculously ships that same day (since it's a Friday). Uh, no clue how fast/slow carriers are there, but I'll be generous and say it takes 2 business days to arrive, arrives at 8am and is set up instantly. That'd be the 26th.
You have approx. one week to mine with this @ current difficulty level, netting you about 2.4 bitcoins (assuming no power outages, no downtime, etc). On the 5th, difficulty changes to ~520m. You have ~10 days to mine at this 520m rate, netting you 2.6 bitcoins. We're at 5 now after 20 days.
I'll be generous and say that from this point, difficulty only increases 25% per increment (last five were 32.13, 27.19, 41.45, 46.02, and the upcoming ~34%). So you have about 11 days on this new level of 650m, getting 2.3 bitcoins. The next 11 days you get 1.73 and going forward you get 1.3, 1.04, .98, .74, .56, .42, .32, .24.
A little over 14.5 bitcoins after 130 days (then it'd be something like 200 days? until you got 1 more bitcoin). ed: +/- 10% from arithmetic errors. didn't use online calculator
Doesn't this thing also use a whole lot of electricity?
So the obvious thing to do would be to buy bitcoin, if you think it's going to be $400...
