It doesn't sound like you really need to use either. You could get by with straight up html and have all those things (that you mentioned, though it sounds like you want some kind of backend db) happen.
I do have some experience using Smarty. Probably the best things about using it, is that you can seperate the programming tasks with the design tasks. By that I mean someone else can design and write the html for all the pages and I can keep all of the programming/db stuff seperate. Unlike a php file where the design and programming are mixed together.
Never touched phplib.