There's actually no limit. Submit to as many directory possible, but choose those that have good PR. Like what they said, choose "quality over quantity".
There is no limit to submit your site in directories, but avoid to submit one url many time in a same directory because many directory take time to approve your website. Some websites take more than 3 months.
I would suggest you to prefer quality directories over the number of directories. You can get a list of free and SEO friendly quality directories from directorycritic.com Also submitting your site to good directories can help you considerably in building a good amount of backlinks to your website/blog which are valued by search engines
You can submit plenty of domains to the directory submission, but only few directories who acknowledge your submission.
Professional Directory Submission Service manually submit your sites to hundreds of SEO friendly web directories.
yes obviously, there is a limit of directories submission in a day and that is maximum 100. After 100 there may be disadvantage for your website.
There is no limit in directory submission per day. The important thing is that in your niche category, u submit your site? If yes then definitely you will get the result and if no then it takes very very much time to get the result from it.
No, there's no limit, but definitely: 10 quality links are better than 1000 low-value worthless links. Another thing to keep in mind is that Google doesn't like if a site gets way too many links in a relatively short period of time. So getting 5 high quality links in two months is better than getting 10.000 wortless links in two days... Beware of the instant gratification virus when doing SEO.