I thought one of the things about bitcoins was that they couldn't be stolen. They're unique, so even if someone did manage to steal them, wouldn't it be possible to just reclaim them by undoing the exchange?
Bitcoin can most definitely be stolen. They rely on cryptography and no central autority. The bitcoin site can explain the detail better than me.
Basically bitcoin wallet are protected by a key which should be kept private (and encrypted with a passphrase). The person who as the key can use the money. Key stolem = money stolen
I think you are confuse qui the non reversibility of bitcoin. This means that you can't reverse a transaction. The best analogy is cash. Once you give cash to someone you have no way to get the money back. This is unlike credit card transaction which are reversable.
Evildragon:
Accepting bitcoin is a cool idea. It might be a bit of work but if you're interested in it it could be worth it. I wouldn't expect that many people buying with bitcoin but we have a pretty computer savy crowd here so who knows.
If you do it correctly I don't think there are that many risk involved. You definitely want to avoid the exchange rate risk as much as possible. Bitcoin exchange rate can be quite volatile. Of course this is also true for "real" currency. More to the point, if you don't actully need to spend bitcoin, there is no reason to keep bitcoin (beside speculating).
There is no reason why bitcoin can't be sold on the market shortly after beeing received. I don't know exactly how other shop do it but there seem to be some payment sytems. Manally trading at a stock exchange (or though an API) is also possible. There is some info at
https://en.bitcoin.it/wiki/Trade
Perhaps the most important is that when using a exchange or a payment processing system there is obviously risk involved. Bitcoin behing quite young, service that which have stolen/lost money are not unheard of.
Just be careful and don't leave too much money in a third party. Any decent service should charge litle fee to do a bank transfer.
One good point for your shop is that the transaction are unreversable. So once you have the money the other party can't just file a claim like in a credit card transaction.
Another thing I can think of is refund policy. If you have to refund somebody it should be clear how they will be payed back. If payed in bitcoin and you pay then back in bitcoin there is obvisouly an exchange rate risk for you. Personally I would just make it clear that refund will be payed in bitcoin but using the current $/bitcoin exchange rate.