Harper's worst nightmare...
The first bit of bad news is this for Harper is that his party isn't the top second choice for voters of any of the other parties. The best they do is having about 26% of Liberal voters having the Tories as their second choice. For comparison the NDP and Green parties are the second choice of 31% and 32% of Liberal voters respectively. This means that if there is a sudden oh-my-god-we've-got-to-stop-Harper groundswell on election day, it's not good news for Harper. The vast majority of the non-Conservative voters have a second choice, unlike the Conservative voter who is 45% likely to not have a second choice at all. This means that in a tight race, there's a good chance of a significant number of Liberal, Green and NDP supporters suddenly voting for whatever party they think has a chance of taking that particular riding.
Which is of course why Harper has been desperately telling people to vote their conscience. If people start to vote strategically in those ridings where it would make a difference, then there's a good chance of a lot of Tories not being elected. If it happens enough, especially with the Tories starting to trail in most regions of Canada, other than the West, and their national lead slipping away there could be a Liberal minority government with a large NDP contingent keeping it in power. Heck, with a strong strategic vote, there could be a NDP and a Liberal MP from Alberta, with the tight races in Edmonton Strathcona and Edmonton Centre.
Of course it all remains to be seen if people will vote strategically. I generally don't, but then again I live in Calgary where it wouldn't do any good in any event. All will be revealed on Tuesday.