I finally overcame my ambivalence about the new Canon 7D and bought one.  I haven’t used it enough yet to say definitively that it has no problems with autofocus or noise, but images like this certainly make me think that the sharpness/resolution concerns are overstated.  It may not be entirely apparent from this web-sized jpeg, but there is amazing detail in this Chickadee’s feathers.  So far, so good.