This depends on the focus of your business and what you want to achieve. If you want to improve your marketing in your eCommerce business, for example, focusing on email marketing apps and marketing automation apps can really help. If you want to run events, you’ll obviously need a good events management app. You can get apps to help with accounting, form creation, shipping … There's a lot of choice out there. One thing you may want to consider getting is a good analytics app. A good app (like the one we looked at earlier, CongaGrid) will be able to break down information in a way that is easy to understand. The more data you have about your business – sales, customer information, clickthrough rates, cart abandonment rates, and so on – the more power you have to make practical changes to bring in more sales. We’d definitely recommend finding a decent analytics app for that reason.