"Good" elementary schools based on what? Based on test scores? Class size? Ratio of teachers to students?
If you are basing "good" on test scores, it would equate with highest income. For income-based rankings, your could use the risk system that they were going to use for the phased rollout of full day K implementation in reverse.
http://www.boarddocs.com/vsba/fairfax/Board.nsf/files/8GGKCC5131BA/$file/Full%20Day%20Kindergarten%20Implementation%20Options.pdf
So the "best" (using the term loosely) elementary school based on lowest risk (or the school with the students with the best financial means) would be Wolf Trap, then Great Falls, then Colvin Run, the Sangster, etc. Of course those "top" schools would also have the highest class sizes.
Personally I factor in class sizes as well, so I would look for a school closer to the middle of the income pack as the class sizes would likely not be as high.