I recommend localbitcoins.com.
It's easy, you don't have to trust a centralized institution to store your coins securely (as Mt.Gox showed, that might backfire) and you don't have to provide them with your ID/proof of residence. They offer an escrow and rating service, so as long as you use it careful, it's safe. Also they work with both € and $, and offer a huge load of payment methods, just choose the one you like most (but not PayPal. It's easily reversible. Many Sellers lost their money by using PayPal). Read the guides on their site for further information.