Technology choice comes much later. 1)First think about who is your target customer/market, what are their problems, how are you going to solve those problems

Technology choice comes much later. 1)First think about who is your target customer/market, what are their problems, how are you going to solve those problems and if you can do it in a profitable way. 2)Decide about what products and services you want to offer to start with. 3)Then comes technology choice. Decide your product's target platforms - mobile, web, desktop, tablets. Then decide on which front-end and back-end technologies you want to learn and use. I think these technologies will be good based on current trends : Back-end : Python, Ruby, .Net , JavaScript(node.js) and framework of your choice. Web based front-end : HTML5, CSS3, JavaScript, JQuery Mobile Front-end : Android, ios , Windows Phone OS Desktop front-end : .Net, C#, WinForms, WPF etc. Personally, I would focus on Web and Mobile apps.