Back to 2009, directory submission was a very popular SEO method, because it was the easiest way to get backlinks, gain exposure, and get more traffics. If you are paying attention to the SEO community, you should be aware that SEO has been changed a lot since then. Some says directory submission has been dead with all those Google algorithms updates. I say it is involving. Back then, people could just randomly submit their website to directories regardless their rankings and relevancy; basically, as long as you submit your site, your are good.
Not anymore, now if you want to do directory submission, you need to dig deeper and research. Find out which directory submission sites are good to submit your websites to. Usually, high PR directory submission sites are pretty good sites. Normally, I would not submit websites to any directory submission site whose PR is less than 4, because it is not worth the time and energy to do it.
Normally low pr directory submission sites are easier to get approved; the higher the PR that a directory submission site has, the harder to get into. For example, the directory submission site Dmoz is pretty hard to get accepted. When it comes to SEO, the harder to get, the more valuable the link will be.
Anyway, for those who are landing on this article just for the List of High Pr Directory Submission Sites, here they are:

High PR Directory Submission Sites List

	Domain Url	PR
1	Sitepromotiondirectory.com	7
2	Highrankdirectory.com	7
3	Abc-Directory.com	7
4	Submissionwebdirectory.com	6
5	marketinginternetdirectory.com	6
6	Siteswebdirectory.com	6
7	dmoz.org	6
8	Usalistingdirectory.com	6
9	Ukinternetdirectory.com	6
10	Gmawebdirectory.com	6
11	Dizila.com	6
12	Promotebusinessdirectory.com	6
13	Somuch.com	5
14	A1Webdirectory.com	5
15	Obln.org	5
16	Addurl.nu	5
17	Ellysdirectory.com	5
18	Splut.com	5
19	Viesearch.com	4
20	Prolinkdirectory.com	4
21	Tsection.com	4
22	Besttobuy.in	4
23	9Dir.com	4
24	Livepopular.com	4
25	Onlinesociety.org	4
26	Pegasusdirectory.com	4
27	1Websdirectory.com	4
28	Synergy-Directory.com	4
29	Gainweb.org	4
30	Ananar.com	4
31	Elitesitesdirectory.com	4
32	Momsdirectory.net	4
33	The-Web-Directory.com	4
34	Happal.com	4
35	Ranaf.com	4
36	The-Free-Directory.co.uk	4
37	Huttodirectory.com	4
38	Aoldir.com	4
39	Free-Url-Submit.com	4
40	W3Catalog.com	4
41	Pakranks.com	4
42	247Webdirectory.com	4
43	Businessseek.biz	4
44	Submitlinkurl.com	4
45	Acewebdirectory.com	4
46	Puppyurl.com	4
47	Baikalglobal.com	4
48	Rdirectory.net	4
49	Picktu.com	4
50	Directory-Free.com	4
51	9Sites.net	4

Please be aware that PR might be different by the time you are landing on this page. Some of them might be higher, some might be lower, some websites might be discontinue or deleted. In any case, usually higher PR diretory submission sites tend to stay longer, because they are more trustful. Also, when submitting sites to high PR directory submission sites, do not just blast away using software, manually submission always have a higher chance of getting accepted.
As always, leave a comment if you find this list is useful; share this post if this list helps you in any way.