The new Radeon HD 4550 and HD 4350 are based on popular Radeon HD 4800 series, but with nearly everything reduced in order to lower the price tag.
Both cards offer 80 stream processors which isn't top of the line but better than stock. They offer UVD 2.0 video processing and support DirectX 10.1 gaming.
Both the 4550 and 4350 will be out in October for around $40 to $60.