The Radeon HD 2600 and 2400 will arrive in June but they may be worth it:
The A12 samples worked at 800 MHz core and there are some indications that the final A14 silicon might be even faster. There is an indication that Radeon 2600 XT should be able to beat Geforce 8600 GTS including the overclocked ones.
The good news for ATI is that its core is made in 65 nanometre production process and won't have big heat dissipation and will easily outrun Nvidia clock by clock. We are still not sure if ATI RV630 will beat Nvidia in every benchmark but we heard that it can beat it in at least a few popular games.