Successor to the Hubble Telescope
The James Webb Space Telescope (JWST) will be Hubble 2.0, and, my personal favorite, it could get a better look at planets in other solar-systems than we've ever had.   Scheduled for launch in 2018.  (Footnote, as Rob Jeffries points out, it's infra-red through long-wave visible light only).   Hence, no Blue/Indigo/Violet or Green, but some yellow.   So, it's not quite like Hubble, but it's still often called Hubble's replacement.

Chandra observes X-rays.

Spitzer observes infra-red.    They both followed Hubble, but they're not the same type of telescope.