Conservatives claim they want to eliminate the deficit and balance the budget, but they refuse to raise taxes and aren't talking about concrete, sizable cuts. Waste will not account for everything they want to do, and a lot of their other initiatives will cost money. Strengthening law enforcement requires money. They're putting all of their eggs in the basket of economic growth through market forces, thus increased revenues, and that's a gamble. Add to it their... somewhat questionable ability to exercise power with temperance and restraint? And I think their initiatives are unrealistic and contradictory.
Liberals are, again, out of touch with reality when it comes to what they promise and how they're going to pay for it. I thought their proposals were even more unrealistic than the conservatives.
NDP isn't that much different than the liberals in practice, but unlike them they don't even pretend to be interested in fiscal responsibility. They claim that cap and trade won't raise gasoline prices, which is absolutely absurd. Worst of all I see them borrowing rhetoric straight from US politics in many instances, and everyone who is versed in US & Canadian politics knows the US is much further to the right than Canada in general, so it just comes off as ill-suited and insulting in my opinion.
Out of all of them, I think if I could, I'd vote liberal. They seem the least of 3 evils right now, I just don't trust the conservatives to govern with any degree of self-restraint and adherence to the rules anymore. I currently live in the US though, so, I don't get to vote. :p