I have an Action that uses this combo. Will also paste it into a new doc if I tell it to. Something like this:
ctrl + a
ctrl + shift + c
ctrl + n
enter to accept New Doc parameters
ctrl + v
ctrl + e
File > Save for Web
Can easily turn things on/off as needed. For example, if I only want a chunk, then turn off the first step, make a selection, then run that bad boy. Or, if I don't want to Save for Web, just turn that step off. Even change Modality as needed. For example, if I want some transparency, turn on Modility for ctrl + n and make sure I have the background set to Transparent. Tons of uses. Very handy.
Combos are great. Toss them into an Action, add some things that you might need, then tweak as needed per use.