How do you host your startup web app?

This is a general survey.

What type of a hosting environment do you use/prefer for your startup web application, regardless of the OS, web server or technologies used?

Choices are:

1. Shared (100+ sites per server)

2. Semi-dedicated (10-50 sites per server, but resources are shared)

3. Virtual Private Server (VPS)

4. Dedicated

5. A custom solution (eg: clustered). Please mention below.