I'd say dmoz is the best but it can take up to 2 months for your site to appear due to every link being manually checked
if you are willing for free submission then try Dmoz,lii, skoobe, ezilon, exactseek, a1searchdirectory. apart from these there are many paid or reciprocal directory list like botw, abilogic etc.
Eemes.com is a website where u can submit ur site for Free. USA Business Directories with Fast Approval
The best directories are the following - Yahoo, DMOZ, BOTW, EZILON.com, Joeant and Business.com - I use all those directories in all my clients submission, my clients love these directories for their good contents and ease of thorough human editing.