Are you guys crazy? Have you even looked at any freaking reviews? 4870 is still 5-10% faster than the 5770, and it will be even more than a 5750. Unless you think that a driver tweak can miraculously change a crappy 128bit card to suddenly out perform a 256bit card, then by all means get the 5750.
4870 is my choice and my recommendation. Just go read some reviews and you will see that the 4870 is better on average than the 5770 and way better than the 5750. Both the 57xx cards are crippled horribly by the 128bit interface.
Back in the day, the Nvidia 6600GT was a 128bit card, and could clock very well, but to reach the 256bit 6800 vanilla performance you had to oc it and yeah you could make it better than the Nvidia 6800 vanilla, but the 6800 vanilla could oc and beat out and oced 6600GT. If you keep things at stock, dont hurt yourself with the cut in half memory interface, it really slows down the performance of the card.
I still recommend the 4870 and 4890 over any of the 57xx series cards. A nicely overclocked 4890 can match the performance of a stock 5850 in some cases, but once you oc the 5850, it wins hands down. For the money, the 57xx series is far to expensive for the performance they give. As always the high end cards of last gen are better than the mid range cards of the new gen. DX11 is a very moot point as well there are no DX11 games. Unless you plan on keeping your vid card for the next 4 years, then you might have to worry about having DX11 support, though all you really miss are some fancy visual things. If that is important then you might want to get the 57xx series, just note that by the time dx11 games come out you will likely only be able to run that game at medium settings on the 57xx cards.
