Yes, Mt.Gox is popular and maybe that is why there's such a long waiting list
I' heard about Mt.Gox and knew they were pretty much the reference for people in America but I didn't know that Europeans could use the site too... What do you mean by waiting list? Does it take a long time to buy/sell bitcoins when you place an order or fix a price for your bitcoins?
Bitcoin-24 and Bitstamp have been suggested several times too so I think I'll try one of the three... Thanks for the replies everyone !