I like the following:
1 BTC or 1B, pronounced "one bitcoin"
and the bits:
1 mBTC or 1 mB pronounced "one millibit" or "one embit" (both pronunciations can be used, I don't see a problem with that)
1 uBTC or 1 uB pronounced "one microbit" or "one youbit"
1 sBTC or 1 sB pronounced "one satoshi"