The elementary schools are pretty good in new Barrhaven. There is going to be a new high school in September 2009. The price of the new houses is now more expensive than Kanata Lake.
If that is the case, I would definitely buy the one in Kanata.
Reasons:
1. The high school (Earl of Match) is good. There are several very good English and French immerson elementary schools.
2. Close to High tech area (suppose your family also depends on it)
3. A lot of shopping stores
4. more green areas than any other community.
5. housing price keep going up.
6. very safe area.