Rather than "unconfirmed"; which is a word that has meaning only to people who are familiar with bitcoin technology, how about doing this instead when displaying the balance in bitcoin clients:
Cleared balance: 17.300
+ uncleared deposits: 2.900
- uncleared withdrawals: 5.100
= Uncleared balance: 15.000
"Uncleared" is a much more familiar concept to mortals.
Similarly transactions with zero confirmations would show as "uncleared".
I'm not sure that I've picked the right way around though; it may be clearer for people to see this:
Uncleared balance: 15.000
+ uncleared withdrawals: 5.100
- uncleared deposits: 2.9
= cleared balance: 17.300
I think the uncleared balance is actually the important one (as we expect that to become the true balance), so it depends whether people think that should be at the top (maybe in a bigger font) or at the bottom.