ImOnCrank, SOAS is near Russell Square/Tavistock Square area, right? That's about as chill of a 'neighborhood' as you're gonna get in Central London...

osiris five, King's College is in a tourist trap called the Strand, across the river from Waterloo station where the Eurostar goes to Paris (soon to leave from King's X as well). Critical Mass always starts on the Southbank just under Waterloo.
SE1? ehh... busy, partly touristy, can be nice but I feel it's a bit neglected. Overall, not a bad area, tho since SE1 is pretty big it's definitely got it's really bad parts as well. What part are ya talking about?