What's the best font size a layout should be designed in when it comes to Header text. Lets say I would want a layout to look sleek but have a personal touch to it. rather than having fancy images and flashy banners, what font would be good use, other than Times?

Isn't that supposed to be your own preference? For me, I'd rather use Arial, Tahoma or Verdana because these fonts looks tidier. The font for the vBulletin Styles above looks also cool. Font size will be 32, 48 or 60 depending on the size of the header. You don't really want to cover the whole header with large text :)

Arial is my favorite - it's clean and easy to read. However, I find that Verdana is usually more popular with members..

My Favourite Font Is Courier New, I Just Love It.