If you don't have Optima (the font), it defaults to Trebuchet, which I find very ugly. Could they not have used one of many available webfonts (from Typekit/FontSquirrel/Google etc.)?
Since it looks like you want to keep it simple and easy; for max compatibility, try just sans-serif. Sans-serif is Helvetica on a Mac, and Arial on a PC. Optima looks really bad at that small a font size, not to mention it looks terrible on a Mac (all smudged). Optima is not designed to be a web/display font.
Checkout Twitter Bootstrap 2 (uut next week) or Foundation. It will make your live so much easier, and the site will be a lot more readable.
http://www.markdotto.com/2012/01/24/bootstrap-2-ready-for-te...
and
http://foundation.zurb.com/