Depends whom you're trying to hide from. Also in US and some other countries having an encypted HDD won't fly in court as they can demand the password and if you don't provide it they assume you're guilty. Also while cracking a strong password isn't possible for most, somebody with high resources like NSA might be able to bruteforce using a supercomputer. Like 7 years ago or so they were able to bruteforce SSL128 in 2 seconds flat. That, assuming they don't already have a solution for easier cracking.
That aside, if somebody beats the shit out of you, tortures you or somebody dear to you, you will tell them the password yourself. So, I guess sometimes actually destroying something is the way to go. for most cases and most people, yeah encryption is great.