"best" link farms??? For the safety of your site, i think link farms should be avoided if you are looking for long term success.
Dont even think about it, Google has been penalizing sites for this. Your PR will be docked manually and if you use Adsense your rates will be fixed.
Yes please do not post your link on a link farm. I did this years ago, and have regretted it ever since.
try to read the link scheme http://www.google.com/support/webmasters/bin/answer.py?hl=en&answer=66356