Most people don't realize that even the finest details in those amazing Hubble images are really rather large, speaking in terms of angular size. They are well within the theoretical resolution of large earth-bound telescopes. Hubble gains by being above the turbulence of the earth's atmosphere, plus it has long integration (i.e. "exposure") times -- it doesn't have to be shut down during daytime. At heart, Hubble is still only a middling 2.5 m aperture telescope, but it has three things the others don't have: location, location, location.