Seems to me a lot of your costs are over and above the actual mining hardware. Even if you return the mining hardware you'll be out a bunch.
Me, I've shut down my miners. Yeah, I'm small scale -- 561 Mhash/sec, cost me $209. Not mining at this difficulty until I know if BTC will be > $4 or under .01 once the smoke from the MtGox fireball settles. =)
I was at an earlier stage in my mining - about ready to order some hardware.
My plans too are on hold until I see just how this all plays out.
My concern is that we may have provided a whole new generation of script kiddies with superb password cracking machines!
This may yet be the main legacy of BitCoin.