On a tip from a friend, checked out Taqueria Los Charros on Dana off of Castro in downtown Mountain View and had to rave a little about it. I had a super quesadilla - your choice of meat, cheese, guacamole, and sour cream all for $2.90! The carnitas were everything I hoped for...meaty and salty but not stringy or dry. It was a little rich though, I would've appreciated some fresh lettuce inside to lighten it up a bit like I've had at other taquerias.
The nachos were so-so but only because I got take out instead of eating there - the cheese congealed on the drive back to the office. Their chips (thin and crisp) were generously covered in sour cream, guacamole, and their very tasty salsa. They also had horchata (sp?) and 3 flavors of aqua fresca - the pineapple was good, refreshing and not overly sweet.
Would love to hear what others get when they go there.