A bit of help determining categories for a new search engine

Hello there,

For some time now, we have had the largest of our three search engines "on hold" (we have already launched Aardvark Travel and Aardvark Sport, but Aardvark Business remains).

One of the main reasons for this delay has been other work commitments, but it's now looking like we should be able to devote the one or two final weeks required to finally get this site of the ground.

Our main remaining dilemma is determining the categories for anyone submitting to the site.

To explain a little further...

Let's take Aardark Travel. If you go to http://www.aardvarktravel.net/directory you'll see the categories that are used for this site. It's primarily a geographical classification in this instance and akin to the all too familiar Yahoo! system, albeit on a much smaller scale. These categories aren't desparately important since most people use the search facilities of our sites, rather than the directory, yet we nevertheless need to get it right.

For some time, we have been working on the best structure for Aardvark Business which will be specifically for businesses, and have been finding it something of a struggle. Unlike Yahoo! we do not have the facility to cross-duplicate categories. By that, I mean we can't have Computers and Internet:Computer Hardware as a category, as well as Retail:Computer Hardware. Well, we could... but we'd prefer to avoid it and keep all the sites that are pertinent to either or both categories in just one place.

Our current "top level" categories are:

Computers and the Internet
Construction and Real Estate
Professional Services
Health Services
Manufacturing and Industry
Recreation and Leisure
Shopping
Transportation

Do you feel this covers everything... I was wondering about "Agriculture" as an additional top level category...

It's also the professional services category that is giving me a headache. So far I have the following which I can't help thinking is very incomplete at this stage.

Professional Services
Professional Services:Accountancy and Finance
Professional Services:Accountancy and Finance:Accountants
Professional Services:Accountancy and Finance:Investment Services
Professional Services:Accountancy and Finance:Loan Services
Professional Services:Accountancy and Finance:Mortgage Services
Professional Services:Accountancy and Finance:Tax Services
Professional Services:Accountancy and Finance:Other Services
Professional Services:Advertising and Marketing
Professional Services:Employment
Professional Services:Employment:Employment Agencies
Professional Services:Employment:Training Services
Professional Services:Employment:Other Services
Professional Services:Funeral Directors
Professional Services:Hair Stylists
Professional Services:Insurance Services
Professional Services:Insurance Services:Business Insurance
Professional Services:Insurance Services:Home Insurance
Professional Services:Insurance Services:Motor Insurance
Professional Services:Insurance Servicesersonal Insurance
Professional Services:Insurance Services:Travel Insurance
Professional Services:Insurance Services:Other Insurance Services
Professional Services:Legal Services
Professional Services:Legal Services:Lawyers and Law Firms
Professional Services:Legal Services:Other Legal Services
Professional Serviceshotographers
Professional Servicesrinters and Stationers
Professional Services:Translators
Professional Services:Wedding Services
Professional Services:Wedding Services:Hen and Stag Services
Professional Services:Wedding Services:Honeymoon Specalists
Professional Services:Wedding Services:Receptions and Venues
Professional Services:Wedding Services:Wedding Attire
Professional Services:Wedding Services:Wedding Entertainers
Professional Services:Wedding Services:Wedding Organizers
Professional Services:Wedding Services:Other Services
Professional Services:Other Professional Services

Can anyone suggest what businesses are missing? eg. private investigators et al...? I've been through obvious channels - Yahoo!, DMOZ, Yellow Pages, etc... so any additional insights would be very much appreciated.

It doesn't matter if we don't get it entirely right from day 1, but the more exact we get it, then the easier it will be as we start processing submissions...

Thanks

Aaron

Hi there, Just running through a pile of business cards from the business network here to see other services for you to consider,

sign writers, designers (interior or graphic), promotional products, Marketing, Human resources, lighting and sound engineers, conference solutions, professional writers, training and management services, auctioneers, domestic/business cleaning services, health and safety laboratory, telecomunication specialists,

Just a few other types of business to consider, let me know if you want anymore!!!!!! Hope it's helpful.

How about governmentals? Like ASEM, APEC,OPEC,EU etc. economical .gov's. Especially FOR businesses they could have handy info, or could have interesting additional info about other links on the site.
No bussiness site has links to .gov's yet. That could have a reason, or you could just be the first one to make it more complete!?