Well Hans, I'm sure you already know my opinion
Smarty is the way I'd go for any PHP site I create. My main reasons:
- Multi-lingual sites become much cleaner/easier (esp. with a few custom hacks to the smarty class allowing you to use the {l} tag)
- Seperating code and html/design makes things cleaner and easier to work on in future.
- When you want to ship off your templates for a redesign, it's a lot easier to have a designer not screw up your few simple smarty tags than working through your php code
- WAP applications as well as other functionality is made much easier with Smarty's functions
I'm sure there are tons of other reasons I could think of if the above wasn't enough.