at some point a month or two from now that might be appropriate. My current models show a price of 0.25BTC for me to see value in purchasing 1 or more with delivery within 3 days.. Some people see value at 0.55BTC, but I don't think that will ever have a chance of returning your investment. Of course, some disagree and that is why you see them being sold at that level to someone.
Every day that goes by, it will drop further, as will my modelled prices I'm willing to pay per GHash. We well could be at 0.1BTC next month, but thats for people to evaluate individually.
I agree 0.25 btc is a good figure. I'd even go for 0.3 depending on convenience/shipping, but give it a month and that's no longer worth it anymore.