I just hiked the Russell Peak Loop yesterday for the umpteenth time and felt compelled to draw attention to it again. This is an easily accessible hike that starts near Happy Valley Elementary School in Lafayette and winds up to Russell Peak (1357 feet) in Briones Regional Park. The views from the top are incredible! You can see the north Bay, Mt. Tamalpais, Briones Reservoir, Round Top at Sibley, Rocky Ridge, Mt. Diablo, and more. This is a great hike to do from Feb-May while the hills are green. I just added a few more details to the original post.
The Undiscovered Hikes of Lamorinda 