I must say that I actually like the small text with lots of line-height. It’s not difficult to read, but it definitely is "different."
On an SEO point: Why is your "main header" an <h4> instead of and <h1> or <h2> ? Do you have three more important headers?
From the <H4> and below is great IMHO. The header is just "off" to me. The Nav Bar is too over-sized for me, and as mentioned there’s something conflicting with the header.
I do like your Nav colors (including the hover) Very professional. It’s just too big imo.
(cool, followed ;))