I'm not that old, but I remeber Debbie Dunning replacing Pam Anderson on Home Improvement. Debbie fit the cute girl that might know a bit about tools way better than Pam did. Debbie is still looks just as good today as she did then.
A sad day for nerds. Apparently half of series 5 of The Sarah Jane Adventures was filmed, but I'm not sure how/if they should wrap things up there. Edit: Here is the story that I got the Series 5 info from.