Software protection and Registration

Sorry to bother with a topic that has been covered in the past but here it is:

My bread and butter software work is protected by a hardware lock, but i have come out with this new utility for the masses I would like to market at very low cost while safeguarding from piracy as much as possible.

I did work on a number of schemes for the registration process, some of which involve HD serial number but I find that limiting because of possible hardware changes.

I have searched this group quite a bit and I understand total protection may not come easy if at all. My own schemes would work not too bad I think but I am still looking for novel ideas or things I have overlooked to implement as good protection as I can. I am not looking for actual code but rather ways of doing things...

What are you guys doing? Any ideas you would like to share?

Thanks everyone.