Being a straight A student except for 2 B’s spread across 4 years is a great GPA.
While GPA/transcript, is an important factor for admission at selective academic colleges, the specific details about how it is used can vary significantly. For example, Stanford was was mentioned above. They recalculate GPA without freshman year and without various non-core classes, sort of like the UCs. They also consider course rigor, how strong the grades are within your planned field(s) of study, and the context of the grades at the particular HS. The reported UW GPA’s of accepted students in the recent REA decision thread are 3.5, 3.6, 3.7, 3.9x2, 3.93, 4.0x4 . The median GPA was a high 3.9+, but there were also some lower GPA admits, who all said they had no hooks. When I was admitted to Stanford several years ago, I fell into the relatively lower GPA group. However, my lower (nothing below B) grades were not in the STEM/objective fields that I planned to pursue in college.
Duke has been quite open about their admission process, which is described at http://www.dukechronicle.com/article/2015/03/ferpa-request-gives-inside-look-duke-admissions-process . An observer to the decisions process wrote, "“If they had a lower grade, they asked, ‘Why did that lower grade occur? What was the story behind it?’” The article also mentions rating students on a scale of 1-5 in six categories, only one of which is GPA dependent. It’s great to get the max 5 rating in that category, but there are a lot of other important considerations in admissions decisions besides just that one category.