Is it practical to paint my house with the colours I want now, and repaint it in a year or two when we choose to sell?

Color is matter of choice and you should feel free to paint whatever you like whatever color you like. Keep in mind that you have to live with what you do and if it pleases you, go for it! When the time comes to list your home, you may find that your realtor will suggest that you repaint if they feel your current choice will affect the sale.