Thanks for the replies and feedback so far. A few observations in response to several of the posts:
Nope. I think they are worth more stored offline nice and safe.
I think of them as digital gold. Would you put your gold in a bank?
I'd argue that safety would be one of the biggest advantages of having a bank that would guarantee your deposits. That way if something like this (
http://forum.bitcoin.org/index.php?topic=16457.0) happened, you wouldn't be out 500 grand.
As for this quote:
A bank would have no interest in doing that as they have no opportunity to use fractional reserves to multiply the effect of your deposit. ie. no leverage. There is only downside for them. You would have to pay them to hold your money.
I'd ask why couldn't use fractional reserves (ie: loaning out bitcoins) and make a profit that way (if, as earlier mentioned, one could figure out a way to ensure that people would pay back their loans)? And even if you didn't do that, I'd argue that there is an inherent value in having access to a large quantity of bitcoins that could lead to monetization opportunities. Hell, if enough people use the bank, one could even make a decent amount of money of advertising alone. Also, something like this would be worthwhile in my opinion, having a bank is also worthwhile just as a way to add legitimacy and stability to bitcoins that could pave the way to larger-scale adoption by the general public.
But there are obviously many, many challenges to implementing this, and I'm just thinking out loud at this stage. Any further observations and remarks are welcome.
Cheers