It is wisest that this reflects what your company sells or the service it provides, rather than your company name, unless this is already well-known. We also recommend registering your domain name as soon as possible. This is because of the time it takes search engines to index new sites. You should place some basic content on your home page, even if the site is not yet ready for public viewing. It can then be submitted to Google, Yahoo and MSN (the only spidering search engines you need to submit to, by the way!) However, be careful about choosing your web host - see further on.
I recall being tickled pink that I could get 'dundonnell-salmon.com' as a domain name for my first website. Little did I realise that 'Dundonnell' has about six possible different mis-spellings, and practically no-one has ever heard of the place anyway! So not a lot of people found us!
The next effort was to try and get 'smoked-salmon.co.uk' or variations on that theme. Well those more speedy than I had got there already, hadn't they?! However we came up with a compromise which actually was even more clever than we realised at the time! 'smokedsalmon.uk.com' - Smoked salmon was the product and if you put that into a search engine you would get 4986 results - so a searcher recognised they needed to reduce that so they often put in "UK", and then what happened - we popped up first! Later I got 'www.smoked-Scottish-salmon.co.uk', which would have been even better because the hyphenation means that search engines can pick out the individual words in the domain name for their indexing, and the geographical reference to Scotland was helpful. Remember also that if you are selling unusual products it is unlikely people will be searching for them, so it may not particularly help to have the name of the products in the domain name. Eighteen months ago I met a man who had spent £10,000 on a website with help from his local Enterprise Company and after 7 months he had only had one enquiry. I asked him what he was selling - 'Scottish Gifts' was the response...... I resented that public money had been put into producing something which was doomed to failure from the start.
Now of course the WWW has been around for a few years and yes, you are right, most of the best domain names may well have gone! So you have to be a bit imaginative now. There are plenty of places on the internet where you can go and play with what you hope will be your domain name and it will come up with alternative endings to help you.
Ideally you should use a hyphen '-' (n.b. not an underscore '_' or a slash '/') in between words because that is easier for the search engines to pick out the separate bits of your domain. For example use 'highland-herbs.co.uk' not 'highlandherbs.co.uk'. However, it is worthwhile booking the latter and simply placing a redirect from it to the former, incase someone forgets to put in the hyphen when typing in the URL. But under no circumstances try to run duplicate sites using the two domains, or try to get indexed by search engines under both domains! Search engines are increasingly clamping down on duplicate sites.
Domain endings (Top Level Domains or TLD's) - of course there are numerous ones now but often you are saying something with your ending '.co.uk' means you are within the UK and you may not be prepared to do business with the rest of the world. Whereas '.com' says boldly you are trading with the rest of the world. However if you have a .uk ending domain name it can help with being linked to within UK-specific search engines and web directories that only allow UK companies to be listed.
It may be that you can find several suitably named domains and that you cannot make up your mind which to have - they are so cheap you might as well get two or three if you really think they are good ones. They can all be 'pointed' at your website anyway. Alternatively, you can have several websites, all covering different aspects of your business, coming at it from different angles. Make sure, however, that you do not simply repeat identical information on all your domain names. Search engines are becoming increasingly sensitive to duplicate content and sometimes "punish" sites that clearly appear to be repeating information that already exists elsewhere. So head scratching time?