It’s not a bad first effort, but it does lack a certain polish which lets it down. As Andy suggested, you could really make a big difference to the overall feel if you put more work into the smaller details.
The first thing that stood out to me was the header, mainly the white outlines around the silhouettes in your logo – in the "Advertise with us" graphic on the right, they are much better. You might want to look at the type treatment on the logo also, it looks very default.
The problems with the header shifting up in various browsers (looked fine in chrome for me, broke in all IE versions and opera) is largely due to the problems in your markup. Specifically this bit:
You need to close up the starting tags for div#identity-line and the logo’s img tag and end the the a href that wraps it. Validating your markup would have shown these problems.
The second thing is that it’s not immediately clear what the site is about. I obviously went there from this site, linking that with your name made me think it was about web/graphic design and I didn’t realize my mistake until I got into the body of your content. Making a short, snappy statement describing who you are/what you do the first thing a visitor sees has become popular for a very good reason.
The only other major problem I saw was some of your images are being scaled via markup. This is what’s making them so blurry, scaling up is always going to cause loss in bitmap graphics, but it’s even more noticeable when it’s done via the browser. Make your images the right size to begin with, and really it’s never going to be bad practice to always make your img tag set the dimensions to the same as they are in the actual file (maybe add probably in there, who knows with retina displays :P ).
This post came out a bit negative (not to mention long) but, honestly, I’ve seen much worse from people who do this full-time. I think you’ve got yourself a good start, you won’t go wrong learning from Chris and the like.