Let's cut them a little slack...
The Conservatives were opposing the ID card scheme at a point before the financial crisis when a) there was still money in the kitty, and b) it looked like ID cards were actually popular. So I think we can assume their opposition is reasonably serious, as they could perfectly easily have agreed with the policy without political cost, but decided (after a few wobbles) not to.
Given the apocalyptic levels of public debt, ID cards won't survive the next election, whoever wins, it's just less embarrassing for Labour to wait until they lose, than to back down now. There's sod all chance of Cameron re-introducing the policy, even if he wanted to, as £10 billion ain't going to be easy to find for a while...
Admittedly various Conservative Home Secretaries fell for the Home Office civil service spiel on ID cards in the 80s and 90s (Waddington, Clarke and Howard come to mind), but from memory none of them pursued the policy and it never lasted longer than a bit of light discussion.
Whilst a certain healthy scepticism is a requirement when approaching all political discussions, there's no need to go over the top - and in fact it makes all debate unhealthy if you assume that all politicians have the worst motives without good reason. It's also an incredibly lazy way to make an argument. Easy cynicism does not equal cleverness.
I approach the prospect of a Cameron government with the thought that surely he can't be worse than Brown, give him credit for the fact that (if he wins) he'll be taking over the the worst economic position since (at least) Attlee, and hope for the best. If his government is crap it will struggle to last even a single term, let alone two.