Bitcoin can be even safer to spend online than credit cards, since you're not handing the merchant your card number which they can turn around and use at their whim.

For that to be a reality, we need to combine hardware wallets (https://en.bitcoin.it/wiki/Hardware_wallet http://www.bitcointrezor.com/), the new payment protocol (https://en.bitcoin.it/wiki/BIP_0070), and escrow transactions (https://en.bitcoin.it/wiki/Bitcoin_Escrow_Service), but the result would be pretty awesome.