A Bitcoin buy site where you can buy Bitcoins instantly using credit cards or bank accounts or paypal etc
Since digital currency purchases are against PayPal's terms of service, no site will be able to offer that. The closest might be how on VirWoX you can buy Second Life Lindens (SLL) with credit card and paypal, then trade those SLLs for BTCs. It isn't cheap, but it is doable.
As far as bank accounts, in the U.S. there is Dwolla for that. Then from Dwolla you have your choice of exchanges where you can convert Dwolla to Bitcoins (e.g., ExchangeBitcoins.com, Mt. Gox, TradeHill, and more.)
in some other countries, bank transfers straight to the exchange are possible.
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http://en.bitcoin.it/wiki/Buying_bitcoinsThere are new exchanges and payment methods being added at an increasing rate. And yes, there is even more to be done.
But neither credit card to bitcoin nor PayPal to bitcoin are likely to happen. Unless it is P2P, with your friend, a family member or a neighbor.