I would recommend starting with something you enjoy, find a wholesale supplier or make the goods/services yourself, and setup a store with eBay.  This is really quick and easy (AKA: cheap) to start.  If you don't know exactly what you want to do it is a good way to see how it will work without a huge investment.  If you are successful in that marketplace you can take it to the next level and expand into a more traditional business model with less risk!  \n\nTry playing around with writing a business plan and see what your risk and financial tolerance is.  The link below is a good tool for planning a new eBay business, I would recommend you check this out first!
What's a good home based business?