I just see the same Pligg site everybody has plus a header not matching the content color nor the width. IMHO you should work your CSS to make everything fit, it doesn't look very nice right now
overall ok, you scan still squeeze some header space by putting your logo on extreme left and having the search box on another column but same row with the logo.
The header looks great. I love the logo and use of colors. It starts off very rich with the blue search field and sign up button. Unfortunately it is downhill after that. Below the search just does not seem to match for me, plus like gaucho said it looks similar to many other pligg sites.
It can be saved, if you can use those rich colors on the bottom half like you did on the header it will give you something nice to look at. Make users want to come back.
And of course if you value my opinion please feel free to leave some rep