Well, go to Old Redwood Square located on the West side of HWY 101. There's some great antique shops and a great coffee spot where I used to work. Way back when.
Fondest memory: You could not trip on any given Saturday morning in the fall without falling on a youth soccer game. I played in Rincon Valley for 12 years. Every Saturday from September till December was soccer and it was a lot of fun.
Go to Railroad Square which is on the west side of HWY101 at the downtown exit. It's a great little area of about two city blocks lined with wonderful antique stores and gift shops and great restaurants.
Fondest memory: Every Saturday morning in the fall every school field in the city was filled with shouting partent rooting for their child's soccer team I played those Saturdays for 15 years and they were great.
Visit the wineries in Kenwood, just south of Santa Rosa. They're some of the best in the nation. I'd recommend Kunde and Chateau St. Jean. Visit in the late spring or during harvest time in the fall for the best views.
Fondest memory: Santa Rosa is a town that has grown significantly in the past 20 years. Fortunately, it has maintained its small town feel from neighborhood to neighborhood.
Downtown. It is full of historic significance and is only a few blocks square. There is an Indian restaurant, a few Mexican/Spanish restaurants, a Vietnamese restaurant, and a few dance clubs, as well as a few bars and a pool hall. A very happening night spot.
Fondest memory: I go to school there, as well as work there, so I'm not away much. It is a very fun, youthful city.