So, I\'m new to dynamic web design (my sites have been mostly static with some PHP), and I\'m trying to learn the latest technologies in web development (which seems to be AJAX)
You got the trade-off correctly. However, keep in mind that you can activate compression in the server side, which will probably make adding repetitive markup to format the table a small bandwidth cost.
Keep also in mind that writing Javascript that works in all browsers (including hand-helds) is more complicated than doing the same server side in PHP. And don't forget that the "new JavaScript optimizations" do not apply to the same extent to browsers of handheld devices.