The hosting companies I worked with are based in France and are a little expensive.
As for the platform, as it usually is the case with PHP, I suggest you go with LAMP (Linux, Apache, MySQL, PHP). Symfony uses PHP5, you'll need to install that version (Also, Symfony is full OOP. In case you have some old procedural habits, you may find it a bitch).
One thing about PHP + Apache: You can only (well amlost only) work in prefork and Apache's
default value are ridiculously high.
I tend to prefer PostgreSQL over MySQL, and chose Debian as a Linux distro. But those are really personnal choices, and up to each's preferences.