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"