I am interested in creating a website whose content comes from a database. My first intention was to utilize Amazon's services such as SimpleDB and EC2 for the code and data, but I worry that this is not a good long-term implementation should I require additional flexibility or run into restrictions from Amazon.

If you are familiar with Amazon's database service, what might you list as advantages and disadvantages of their service? As alternative, how "easy" is it to set up a database elsewhere using MySQL? And where might you suggest I go for hosting?