All are around the same price (£95-£105), which performs better, I'm not bothered about power usage or media encode stuff just pure gaming performance (at around 1080p resolution).
Thanks in advance
The 550 Ti is better than the HD 7770 ! http://www.hwcompare.com/11894/geforce-gtx-550-ti-vs-radeon-hd-7770/ it even perform better at higher resolution because its higher pixel rate...