Yes and no.  The vast majority of all searches will have the data pulled from one of the major search engines or directories we have listed here.

Often getting a listing in one place will lead to being listed in others.  For example, most people are not able to get a listing in the Yahoo directory.  However, Yahoo uses Google for it's search engine component, so submitting to Google is valuable.  For more information on each of the major search engines and directories and how they are fed, this site is very good:

http://searchenginewatch.com/links/major.html

There are also many local directories that might be unique to your industry.  I'd suggest looking at these and submitting to them individually. 

You might receive spam occasionally advertising companies who will submit to thousands of search engines for a 'low price'.   However, it is important to know that the vast majority of sites that they submit to are not search engines or directories, they are simply doorways to other search engines.  In essence, those submissions are useless.

Also,  if you wish to do business only in your area you do not want to list your site on European or Australian search engines.  Likewise, if your business is 'interior design' for example, why would you wish to be listed on a search engine that is geared for "Football" or some other non-related topic? 

The greater problem with the bulk submission companies though is that you can end up paying for something you can easily do yourself and the end result is you receive a lot more spam because of it.  When you submit to any bulk submission place, be careful that you aren't simply providing your valid email address to a company who is going to place you on their spam mailing list. 

This is not to say that there are not some reputable companies that provide a good service for submitting to search engines.  These companies will work with you to choose suitable keywords, assist you in modifying your meta tags on all major pages and customize those pages with unique words, submit on a regular basis to the search engines and give you reports on the results of the submissions as part of their service.

For more information on search engine submissions, please contact us at:   info@thenetnow.com