That can be 0.1 BTC or a few hundred. Seeing that your account was created in the December 2013 bubble I guess you're closer to the former number...
Anyways, feel free to choose, you already got some offers after all.

A last reminder: BTC you have on any exchange are not yours: They belong to the exchange and (hopefully) you can redeem them later. If you only trade with e.g. 10 BTC usually, withdraw the remaining ones to a secure location, like a paper wallet. Trading with all what you have all the time might be a stupid bold strategy by the way.