Technologies and Coding?

If you were to develop a Web Application from scratch, the key focus of the application is -

- Many daily transaction
- Institutional look and feel
- Reliable and responsive
- Security
- Support

I am doing a case study as part of my University dissertation. I have had many different views from 'industry experts' and general people, but have had many different answers. I want to put the question to a forum to get some impartial answers.

So What technologies, code and if possible MCV structure would you use and why?