General discussion / recommendations re: Bitcoin mining

[Onus]

I've been reading a lot about bitcoins and bitcoin mining. A good place to start learning about various configurations seems to be here: http://www.hardocp.com/article/2011/07/13/bitcoin_mining_gpu_performance_comparison/
What little I see around the Forums here seems to be mostly moaning about all the high-end AMD cards being scarfed up by bitcoin miners. I'm not out to inspire a flamewar or cursing, but I am curious as to whether or not this might be a worthwhile thing to start doing, even on a small scale.

I would appreciate the general thoughts, comments, and recommendations the community has to offer on this topic. Any of you doing it? What kind of return might be reasonable to expect?

 

[Onus]

Update: I tested some bitcoin mining off and on this weekend, using a single HD6790. I couldn't run it with a real high OC because the case it's in (a PC-Q08R) doesn't get rid of heat too well (GPU at ~85C, mostly idle i5-650 at ~61C), but it looks like so far I've probably netted about $1.50-$1.75. At this rate, but run steadily, it will likely pay for itself in just a few months, so I may get another HD6790 and put them in another box.