I have been using ezSQL for the last few years but feel it is outdated. Though I like the simplicity and I like the file based caching ability with json, for small result sets that is.
So starting a new project I was looking for suggestions on a better mysql class for php. I know the db will only be mysql so portability is not a requirement. I read about mysqli extension, pdo etc but just dont know which one would be best for my situation. The site does a lot more reads than writes, though there are times where there are a lot of writes in the admin tool to the db. I looked at doctrine but dont know if that is too "bloated" for what I need. Hopefully this isnt to vague. Any suggestions?
EDIT
The site isnt small, I would consider it a high traffic site with a lot of db queries.
From what I know of ezSQL (via it's wordpress pendant) I would consider Doctrine as well as too much for the moment because it's a complete data mapper for the database whereas you might be more looking to how to move away from your recent use of ezSQL which I think is a good idea.
Bascially you might be interested in a data-access abstraction layer. That could be PDO as it's build in into PHP. Even if you don't need to change the database server, it will give you defined interfaces how to query and access the data.
As you build the site from scratch, I can suggest you consider using some lightweight framework. A good introduction in my eyes is When Flat PHP meets Symfony which shows how a webapp can generally benefit from patterns and a flexible design.