Any protection can be cracked (IMHO). The trick is to make it impossible to create a keygen or single user names/serial number pair that any noob can use. As long as it requires a patch you can minimize the number of cracked copies by using embedded/protected/encrypted custom key checking and updating your releases often. This will:
1. force the cracker to disassemble and nop/remove the checks to create a patch
2. make it difficult for the noob to find the matching software version and patcher
Keeping 1/2 step ahead is the best you can hope for.

As to commercial packages, I gave up an built my own (using lots of information from exetools, thank you very much). The two I did use where:

CypKey: Pretty good protection, too expensive, has a habit of eating user's keys for no apparent reason, no re installing of os

SDProtector: Absolute crap. Based on some copy protection on planetsourcecode.com. Very incompatible, terrible support, barely works

Hope this helps, wcff