This is a good thread so I thought I would drop my opinion in.
Google doesnt want webmasters creating links back to their site. They want other webmasters and Internet users to post links back to websites that they feel can offer some type of value to other Internet users.
The Google Link Algo was originally based on how references were used in Scientific/Medical/College papers. For example, a group does a study and publishes a paper. If many other groups, students and studies use that Paper, or pieces of that paper in thier new study or publication, then that original paper must be of some relavence.
So with that said, if you are creating the links to your site then you are trying to game the system. Obvisously, Google must know that any serious webmaster is going to build links. So there are ways to do your link building that are more favorable then others.
"White Hat" methods in my opinion would include article writing, blog postings, relavent blog commenting, or just about anything that involves getting a link from another website that is related to your site.
The only difference with what many people consider "Black Hat" is that all of the above is done, just more automatically, and in much higher volume. In my opinion, I consider this Grey Hat but many would disagree.
As for me, Black Hat is when someone Hijacks an legit EDU sites and sets a redirect to their money site. Funny thing is that Viagra and related pill market is loaded with some very Dark methods. Google Viagra Online. Look at the 7 result! Penn State! LOL.
But also do Buy Cialis Online. A bunch of EDU hijack redirects.
Personally, I would love to do this. There are many ways to try some of these methods without worry of screwing up your other sites. So if anyone knows how to do this, I got deep pockets and great places where to make a killing with this.
As for what is better Black or White....its all great and all should be employed in various degrees and for different applications if you are a serious full timer.