Font sizing best method? em vs % vs pt vs px vs text?

[gwmbox]

One of the many things I stumble along on many web sites is the different methods used for font-sizing. Even worse is when you see some sites use 3 or 4 different formats in the one css file.

I have always preferred either 'em' or '%' but I am wondering what the norm is these days and what is regarded as best practice and why. I am also interested to hear from (or should I say read) those that may not agree with what is an accepted best practice and why they choose to use something different.

So what do you use and why?

Thanks

GW

P.S. No this is not a homework assignment I am way too old to study :P

[jscheuer1]

These days it doesn't make all that much difference. There was a time, when IE 6 and less were the predominant browsers, users couldn't resize text set in pixel units.

And, for all browsers, if your main objective was printing, inches or points might be a good choice. But now most browsers allow you to manipulate (or manipulate automatically) the font to get a good printing of a page, as long as it's laid out with printing in mind.

Using em's or % was, in the older days I'm talking about, the best for pages intended to be used on the web. Percent actually the best. If you set text size in % and things like widths, heights, larger margins, and larger paddings in ems, things worked out well when resizing the page and at different resolutions.

Now most browsers have zoom or a zoom like utility or their resizing utility is really like zoom, so it doesn't matter what you use. What zoom does is treat the page as though it were one single image and make it larger and smaller uniformly.

But for purists though, it will probably always be % for text and ems for dimensions, unless it's for printing.