content managment systems

I am looking for open source CMSs that: 1) use PHP/Mysql 2) are relatively easy to install, for someone familiar with both PHP and MySQL 3) also easily allow you to change the layout/template from the default For instance, if I want to hire a graphic designer to create a static page for me with a unique design for my site, I want to be able to create a template file from that (possibly one template for the home page and a second one for inside pages) and then plug in a CMS into that layout (or plug the template into a CMS) so the client can then make any changes to any pages without having to go through me. I've heard PHP-Nuke is a very good portal system - would it work for this? Any other recommendations? The CMS must be open source, the budget is very limited right now. Thanks! -Lisi