JJG, that's why I like the mining investments.  It's virtually risk-free, since the ROI is so quick, and even if you don't hit it, the hardware can be resold for nearly as much as the purchase price, especially if you are a frugal shopper.  But yes, it's still hard to say what will happen in the world of bitcoins.  The price could drop below $1.70 tomorrow, which would make my mining unprofitable.  Who knows...

IMO, the 6990's are a terrible investment, unless you just don't have room to have several rigs.  Going with a midrange card, (ideally a 5830/5850/5870, though those are difficult to find for decent prices anymore) will generally give a much better MHash/$$$ rate.  As it is, you are lucky to get 1Mhash/$ with a 6990, but a card like a 6950, which can get 400MH/s with a bios flash, is nearly 2Mhash/$.  Of course, system costs must be taken into account, but with the spendy PSU's required for a 6990, I just don't see the point in spending the coin on them instead of a cheaper alternative that gets more MH/s.