Choosing a domain name is a really important branding decision. Whenever possible, register your company name as your main URL (domain name/website address) because it is what people enter first when searching for your website.
You should also look at registering your product/service names as additional URLs. Some companies create mini-sites specifically for products and services or you can use these URLs to point directly to the relevant section of your main website.
Buy up ‘common’ misspellings of your domain name, this means you won’t lose any potential traffic and competitors won’t be able to buy those domains to siphon off traffic intended for your site. The only real defense against typo squatting is buying variants of domain names that might be hijacked by your competitors and this includes purchasing the singular/plural, hyphenated/non-hyphenated versions of your domain name. Be careful though as there is no end to variants, add a word, create a plural….. my advice to the marketing teams of the brands I mange is to make sure you only use the main URLs that match the brand / product and not diversify. The more you diversify, the more you leave yourself and your customers open to cyber-squatters.
If your business is very regional then register the company/service name and the town in which you are based in order to make searches as local as possible. The best way to think through your domain name is to consider the process you have gone through when searching for something very specific and/or local and think about how you have had to refine your search to find a relevant result. By placing yourself in the position of your customers, you are best placed to succeed.