Firstly let me say, you're in a very enviable financial position. The banks will no doubt love you.
My advice is go to a financial adviser (I use Trevor at Anderson Financial Planners - PM me if you want his details, he's brilliant), and get them to plan out your future. You're in a position to create some real wealth if you plan it right.
You will lost likely find that a level of debt is required to achieve this. Owning your own home outright sounds fantastic, but it's a bit like having $200,000 worth of shares in one company. You need to diversify a bit and protect yourself. If the housing market went down the shitter, all that money you've made will be lost again.
You've done really well to get to where you are, so get professional help from here on in (as an aside, financial advisers make far more money for you than you ever pay them...).