If you are in the US, Look into Coinbase or Dwolla+CampBX. Dwolla and Coinbase link directly to your bank account, and moving money from Dwolla to CampBX is almost instant. Then you can use either Coinbase or CampBX to trade the USD for BTC, and then send it on to your wallet.
Every once in a while somebody pops up with a website selling bitcoins directly paid with credit card, but none of them have lasted very long.
CampBX also allows transfers from some banks without Dwolla - 3 day delay I believe but one less intermediary.
I was under the impression that BX only allowed withdrawals with banks, not deposits. Is there an option I'm missing? They accept Dwolla deposits, money orders, and personal checks (with verified accounts). I literally just looked at the "transfer" area, and there's no other options for deposits.
That would be pretty damn handy if they accepted wire transfers.