The number of applications in the app store is approaching 100,000. The quality of applications in this massive of a marketplace is hard to measure. Apple provides the star ratings for applications but I like to have a few more sources. Check out:
app.itize.us is a site highlighting the best of emerging apps in the store. The site is really well categorized and will surely show you some hidden great apps.
Fresh Apps is a user driven review site to supplement the star and comment sections of the App Store which was created by iCodeBlog contributor Brandon Trebitowski (brandontreb). User can get an account and set apps as “Fresh” to boost their popularity on the site.
Touch Arcade is a very popular iPhone game review and preview site. The site was created by the founder of Mac Rumors and is a one stop show for a look at the most quality games on or coming to the store.