I would not recommend buying any equipment you were not going to buy anyway.
If you look here: http://bitcoinx.com/charts/
you can see a chart showing how the profitability of mining is quickly disappearing. Look at the chart that shows USD/24hrs for 100Mh/s.
The only reason to bitmine anymore, is if you already own the equipment and
you get free power or you can use the waste heat that the rig produces for free heating. If that's not true for you, stay away.
Truth in advertising, I am looking into this myself, but only because the above conditions are true for me.
I don't see any real price support for Bitcoin/USD until around $6.50 and there is no guarantee that it will hold there. All of the price movement to date suggests that the price is still falling (I wish it weren't). I used to trade stocks and options fairly seriously, so call this an educated guess. I personally believe that Bitcoins have a real non-zero value based on utility and user base, but whether that value is 10 cents, $1, or $10 I couldn't say. I doubt that it is currently over $10 though, and I would not be surprised to see it fall to $1.
I imagine that a lot of the interest in Bitcoin so far has been from miners and speculators, and when both of those things become unprofitable we could see a collapse. Hopefully the worst is behind us, but don't bet on it.