Keccak (Smartcash, Maxcoin): 136GH/s (17GH/s per card x eight) ($160/day at Apr-30 prices)
Tribus (Denarius, Virtus): 16.8GH/s (2.1GH/s per card x eight) ($304/day at Apr-30 prices)
Phi1612 (Luxcoin, Folm): 5.2GH/s (650MH/s per card x eight) ($456/day at Apr-30 prices)
Skunhash (Various coins): 10.4GH/s (1.3GH/s per card x eight) ($261/day at Apr-30 prices)
Those yield around US$20-$57 per card per day ($160-$456 per day for the rig).
This is a mutually-assured-destruction arms race.
I calculated for Phi, if there are 5000 such cards online, the per day return will be $12 per card and not $57. (The GPUs will make pennies, meanwhile.). That will be an year to get back cost at $4000.
And 5000 is conservative number I think, for one Algo.
Edit: And the irony of this -> Only ASICs will survive.
ASIC's are only really going to survive on coins that aren't building resistance into their algo's.
Then we have a the FPGA's and GPU's battling it out on all the rest
