I will put AnandTech on top of the list. But they do have a bias for the companies which allow them easy access. Intel helped them a a lot in beginning so they tend to see most things with a shade of blue. They have a soft corner for Apple, OCZ (SSDs) and sometimes Nvidia. But mostly the site is very thorough and when it comes to calling spade a spade, they don't hesitate. Anand's work in shaping SSDs has been phenomenal.
Guru3d is rubbish... they give all products a five-star rating.
Hexus is good, Hardocp is good, Techreport is very good (never take any sides), Xbitlabs is OK but has shown a liking for AMD in recent times.
Bit Tech is very good and is particularly harsh on any shortcomings a product displays. Even if the product is good, if they find anything that could be a deal-breaker, they totally crap the product rating.
Getting a good rating at Bit-Tech is very difficult. Take for example a recent Asus high-end mobo they reviewed. It performed excellently and had an amazing feature set, but Bit-Tech advised readers not to buy it because in their labs they had a new Gigabyte mobo that is performing equally well but at a lower price. I don't see any other website cutting points from a product on the basis of another product that will be launched two weeks later.