Leverage = The amount/type of bullets you have
Gun = Broker which you use
Trigger of the gun = Your bias towards the market (what you believe the market will do)
Vest = Your stop loss
The interesting part of the 4 things listed above isn't the leverage. As the gun can not be used to fire unless someone or something is present in order to pull the trigger. The killer of all accounts is a combination of the Trigger + Vest + bullet (with that order being the most important). A combination of the three is what we know as being the "money/trade management".
Most of us have heard about "not risking more then 1%" of your account, but the reality is the first trade which you place sets off the bias which you will have for the life of the account. If you buy say EU and the trade goes against you, then the reality is every time the price drops, you will be looking to buy more, thus ignoring Price action which determines where the currency will go now, and in the future.
You may actually risk 1% of your account, but adding more trades, or not simply aiming for accuracy is what blows the accounts because by nature, humans have been designed to ignore price action, as we believe we can predict what a currency will do.
If a person on avg doesn't give the market more then 20 pips before closing profits for a trade, no matter how many pips he or she takes in profit, then your money management or better yet, the type of bullet (leverage) should be determined based on that. I personally have seen on another forum, a guy who has a 100% win rate, but the amount of pips he has of floating loss exceeds over 400 pips. At times, even thought, a 400 pip floating loss may not be more then 15% drawdown the reality is 400 pips is way to many pips to be giving to the market no matter what tf you are trading.
So to the new traders, and please take this from a person who lives from trading, focus on being as accurate as possible. Do not take a trade based on news, nor on opinions of anyone because when those trades fail you will be the one left holding the bag. If you can find accurate entries (entries in which you give less then 20 pips to the market before you close for profit) then the reality is you can wager 1% of your account per pip easily as long as you stick to your hard stop loss.
To sum it up, leverage isn't the killer of the account, but the actual system and the comfort people have when they say the market is cyclical, so the trade will come back to me at some point.