I think you should stay with PHP, but you can introduce other sexy things like utilizing the cloud servces. Swapping Apache and mod_php with Nginx and PHP-FPM.

I think you should stay with PHP, but you can introduce other sexy things like utilizing the cloud servces. Swapping Apache and mod_php with Nginx and PHP-FPM. Use NoSQL stores like Redis, and MongoDB. Take advantage of HTML5 and CSS3. Look at websockets and Chrome's Native Client. Think about resposive design, and mobile first approach. Design a REST-API, and allow for easy integration and data fetching with OAuth-authentcation. Think about building native mobile clients. There is so much to understand, and do these days that the language you use to goue things together isn't that important, and btw PHP is one of the best languages to glue things together.