We should definitely strive to discover what the cause of this breach was.  Was it a trojan or keylogger on the OP's computer?  Did someone find a new security hole in MtGox?  CSRF attack?  Phishing website?  Etc, etc.

There had to be SOME cause to it, and pointing fingers at either side isn't going to do any good.

Where did you store your password?

I love bitcoin and the whole idea of being able to  Hande more freely, but I'm also getting tired of constantly being put back.

I'm not one second of doubt that if MT Gox was not hagget last time, so bitcoins had been worth $ 40-60 today ... this does not help that there is more security about the exchanges we user. and I have made risk spreading by using several exchanges have little bitcoins in each but it does not help a damn thing ... think I'm done with bitcoins ....

Mac

A sucker is born every minute.  I'm sure whoever got them from you is enjoying themselves. 

Well running a mac surely throws out 99% of virus and typical internet attacks.
The other .99% can be defeated via updated software on a regular basis leaving only 0day attacks and blatant
mistakes by a user who runs untrusted software and otherwise clicks YES to anything that
pops up on his desktop.

Do you run all sorts of goofy software found on the internet? Especially odd bitcoin related software?

rotfl

You said you had a unique, long and secure password. I generally do not expect people (like myself) being able to remember them.
Did you use a service like LastPass or did you have the password written down in (encrypted) text somewhere (inside or outside the computer)?

MTGOX uses https for auth.. so it is not like a man in the middle attack is trivial.

Also, it seems the user is not a noob running windows XP with sp2 or what not.

If I was MTGOX I would be taking this post oh so seriously as an attacker of the MTGOX
website would surely go about draining accounts in a slow methodical fashion versus going
all out and alerting many people at once.

If they were owned once.. it can happen again. Especially when an attacker knows there is
a currency that can be transferred anonymously.

The OP seems to have his bases covered unless, no offense, you are not telling us exactly
how you use this apple mac computer. Perhaps you like to view odd things online going to
several possibly malicious websites per day?