Best methods of Wordpress optomization
Ok, I'm setting up a few wordpress installs. I know there are all kind of optimizations that I could do:
1) Use Nginx instead of Apache
2) Use FastCGI
3) Install Varnish
4) Memcash or Reddis
5) Various plugins like WP Super Cache.
6) A bunch of stuff I probably haven't thought about yet.
In your opinion what would be the right mix or a good mix with minimal hassle. I KNOW you are going to say that depends on visitors, usage, plugins, etc. I don't have that info yet, as they will be new sites. They could only get a few people a day, they could go viral and I'd have to start throwing a lot of hardware at the problem. Most importantly, I want to learn from your experiences.