Bitcoin Dice - provably fair
Sportsbook - provably fair
Bitcoin Exchange -

Exchanges need to be provably solvent, do they not?

I think the remaining exchanges will need move very quickly to prove themselves and subject themselves to external audits.
Minimally they have to prove that customer funds are segregated into one address per customer and that the exchange indeed holds the keys
to those addresses.

Coinkite seems to be on board already.
http://blog.coinkite.com/post/77699705732/updated-audit-report-transparency-and

edit: Looks like they're on top of it.  I hadn't read the statement at http://blog.blockchain.info/2014/02/25/joint-statement/