I would suggest the Asus 7750:
http://www.newegg.com/Product/Product.aspx?Item=N82E16814121633
If only because I know the fan is very quiet (and Techpowerup concurs), and the fan is a 4 pin, PWM controlled fan, the GPU is shock mounted (not necessary, but nice to have), and the PCB is well cleaned before it left the factory. Mostly small subtle details, but since the cost is nearly the same...
Otherwise, if you prefer non-ASUS, then stay away from the Core edition by XFX. That one has the least warranty of all the cards you listed.
Of the 7770s you listed (you listed 3 7750s and 2 7770s), they MIGHT work in your computer, since the TDP is only about 20 watts higher on the 7770 compared to the 7750. But I don't recommend a 7770 for <300 W PSU. I'm almost certain you'll get away with a 7770 with your PSU, but you'll probably want to not load the PSU too close to its maximum when CPU+GPU are stressed, and you inadvertently plug in a USB hard drive or something. Plus, leaving the PSU not fully loaded should lower its temperatures and lengthen its life span.
At this point of time, I will NOT recommend a 6670. But if you HAVE to get a 6670 (although I'm not sure why), be absolutely sure to get one with GDDR5. The DDR3 version has less than half the memory bandwidth of the GDDR5 (full-fat) version.