I'm gonna keep them. Even if they go down in value any extra sale is presumably generated by a customer I would not had otherwise (Bitcoin customer).
If not, just quote some average price, for example from preev.
I'd like to quote a price which makes the customer confident she/he's getting a good deal.
So far Mt.Gox seems the best for the buyer (and worst for us, but this is fine).
Also, I'd like the customer to see this before, not waiting for my quote.
This is the reason why I can't quote the Bitstamps price: the customer wants to see Euros and won't see them there.
And I'd like to spare him the effort to make the USD/EURO calculation in his mind.
P.S.
We don't sell goods and don't pay for what we sell so we can afford to lose the whole transaction (would not like to, but are not damaged by it).
So this is actually an interesting scenario where BTC adoption could spread as the risk is really low, even in case of crashes.