What's your budget? And you do realize that ALL current boards will support the 5770, right?
I would look into the X3 425 and Asus M4A79XTD EVO. For RAM, look into 1600 mhz CAS Latency 7 (timings 7-7-7-x) dual channel kits if you want to overclock. If you don't want to OC, grab some 1333 mhz CL 7 sticks.
I have no idea on prices over there, but over here that should be about $300 (~200 pounds). If you can afford a bit more, switch the board to the Gigabyte GA-790XTA-UD4 if you want USB 3/SATA III support, or up the CPU to the X4 620, X4 925 or X4 955 unitl you hit the budget.