I am using FF 2.0.
The website is very nice, clean, and I like it a lot. Very good!
One thing I noticed right off the bat was the tabs, I love them BUT the active tab seems out of place to me. I would put a grey border around the active tab, to kind of tie it in with the border (below the diagonal lines).
This might be kind of hard to explain, but I will try. I am big on keeping a website size down for fast load times (yes, even with the blazing high speeds everyone seems to have)... Your header image is 131KB. WAAAY to big imo. You should optimize it down as low as it will go without losing quality. Next thing you do is cut a small sliver off. See the solid image colours on the right and left side? cut off 1px of that, and make that your header background image.
What that does is make a very small image for your header background (the one the repeats throughout the width of the browser) and it lowers load time. Then you just cut off the excess image of the header.
This will also take away the vertical scroll I am getting, my resolution is 1280*800, and at that resolution, it is simply unacceptable.
Do you get what I'm saying?
I figure for me to get feedback, I should leave some, so please review my website ;-]