bitstamp and btc e looks safe, but no one is hackproof,
so, never leave big amounts on the exchanges

BTC-E has been around for almost 2 years now, and they have never been hacked. (The owners themselves are some very good hackers.

).
Indeed you have mentioned that in page 1 in this thread, and people have already pointed out it is not true.
Btc-e got hacked in 2012 and they lost around 4500 btc, which they covered from their own pockets. Localbitcoins was hacked recently, with people who had coins stored on their localbtc wallets reporting they got robbed. Every exchange can and will get hacked. Even giant corporations and governments systems get hacked frequently.