I would change the background, looks a lil bit girlie.. Also for my taste it's too dark. Work on margins, make nav elements bigger and more web2.0 style
Design looks good, quality of a theme also depends on how much customisable it is by normal users. Being SEO friendly is also a feature to add, maybe using theme options page. You should also add a good pagination build within the theme.
I think that it's a decent enough first attempt. This is the kind of thing that I was putting out with Artisteer for my first attempts. By spending time getting to really know the software you will be able to create some great looking templates using Artisteer. I still use it now and absolutely love the improvements made in v3.