The convention I hold to quite carefully is to call the technology "BitCoin" and the money itself "bitcoins". This is largely so that even at the beginning of a sentence it can be clear whether I am referring to specific coins or the technology as a whole. It is an arbitrary choice, but I feel it improves communication of the concepts.
Alternatively, try using Bitcoin for the technology and BTC for the money. Though, for those of us familiar with Bitcoin, context is sufficient to differentiate Bitcoin the system and bitcoins the money.
"What a fascinating system Bitcoin is"
"I have 10 BTC or 10 bitcoins"