This is an entirely different question. Anyway, I have bought BTC 70.
But do not delude yourself that you can foresee the short-term future price of bitcoin. If you could, you probably would have better things to do instead of posting here.
Back to the original topic: still no transaction after 90 minutes.
You understood that I was speculating myself, right? I don't work for Bitstamp.
Like I said, I believe larger withdrawals have to be confirmed manually. Depending on the time of the day you request it, it might take until the next working day for that to happen, although, I never had to wait that long.
If 90 minutes withdrawal time from an exchange is too much hassle for you, I suggest you don't leave your coins on the exchange in the first place. The blockchain is fast, human supervision & security, less so.