Without getting into the finer details here...
HH-60G (same thing as MH-60G) - U.S. Air Force dual role of Special Forces insertion and extraction as well as Search and Rescue. The "Pave Hawk" is flown by both active duty and ANG units here, Alaska, Japan and Iceland and have been deployed worldwide. Color weather radar is carried in the thimble radome off-center on the nose and now you'll see more and more using a FLIR turrent mounted on the nose as well. Some Pave Hawks carry a radar mounted just like the MH-60L, but I don't know if it's the same one. For the longest time, Pave hawks carried a European 1 scheme of two greens and a gray, but some in Desert Storm flew with a two-tone brown and some in OIF flew with a three-tone sand schemes. Now that all Pave hawks are falling under the command of AFSOC, they're coming back from depot in overall Gunship gray. Oh yeah, and even though they could, they never fly with external tanks or even the ESS mounted, it gets in the way of the mini-guns. From the outset, it's had an air-to-air refueling probe.
MH-60L - US Army Special Ops Blackhawk flown by the 160th SOAR (Special Operations Aviation Regiment) out of Ft. Campbell modified with FLIR turrent, weather radar. Sometimes referred to as the AH-60L DAP, the idea of arming a Blackhawk with rockets and forward firing machine guns into a "Direct Action Penetrator" is the brainchild of Cliff Wolcott. He didn't get a chance to get them ready for Panama, but they flew SCUD hunts in Desert Storm and participated in Operation Gothic Serpent in Somalia. You've seen them in "Black Hawk Down." They also had a "too brief but still cool" crucial scene in "Clear and Present Danger" with ESS mounted (probably because they filmed those scenes in Mexico and they didn't have tanker support). All MH-60Ls are painted black with OD markings (barely) visible on them.
Check out the boards here for more on the Pave Hawk. Salbando has posted a lot about them here.
Also check out the walkarounds at http://www.aircraftresourcecenter.com/ there's an good MH-60L gallery in there.
http://www.globalsecurity.org/military/systems/aircraft/mh-60g.htm
http://www.globalsecurity.org/military/systems/aircraft/mh-60l.htm
http://www.globalsecurity.org/military/systems/aircraft/mh-60l-dap.htm
http://www.fas.org/man/dod-101/sys/ac/uh-60.htm