I have been using Joomla CMS for awhile and I love it. My advice is to find themes you like and then proceed to edit them via html and css code to how you want it to look. For individual posting such as static pages, you can edit the html and css within the WYSIWYG editor with ease. I prefer to use the JoomlaFCK editor, or JCEeditor, they are much easier to use if you want to be doing the programming for each post.
There are a couple of components and modules you do need when you are using Joomla though, or else your website will be slow loading and bad search engine optimization.
Sh404SEF
Ircmaxell's Page Cache
Joomla PHP Speedy Plugin
I do use JoomSEO on my websites, but this by preference only, there are a long list of SEO com and mods you can use.
I do recommend comparing the differences between joomla 1.0.X and 1.5. On the websites I have built, I personally prefer 1.0 over 1.5, because certain plugins have not been updated yet to work on 1.5.