From what i've heard all AMD cpu prices will go down to match core 2 prices when its launched on the 24th, so in that way it might be competative.
Looking at the benchmarks, a E6600 is equil to an fx62 in most gaming benchmarks, it runs at 2.4 and the fx62 runs at 2.8 so exactly as i predicted a conroe is 400mhz 'faster' than a K8, so the k8 has to be 400mhz faster than a conroe to be equivalent.
By that logic, the E6400 at about 2.2 will perform on par with an X2 5000+ at 2.6, and the E6300 at about 1.8 will perform on par with an X2 4200.
Apart from the Fx 62 and perhaps the X2 5000+, the others will all get price drops to match the equivalent conroe, so an X2 competing with the E6300 is likely to cost the same, £150.
If that happens, there is no reason to get the conroe over the X2 except for its overclocking potential.