Unless your site is entirely for your own personal use, such as a family blog, you probably want as many visitors as possible. One of the best ways to achieve this is to put your keywords into the url or domain name that you choose. This will enable the search engines that spider your site to pick up on your site.
However, what if you want a title that doesn’t necessarily reflect what your site’s about? For example, if you business name is Jones & Son and you don’t wish to change that, and you sell leather goods, you can buy two domain names and point them both at your site; one that says jonesandson.co and one that says leatherhandbagshoeshop.co… or whatever.
You can find out what keywords apply most to your site and products using simple analysis programs that you can get free on the net. You put in a description of your site and or products, and it generates not only tags and keywords, but can often recommend which are the most popular keywords.
You should ensure though that your webhost allows multiple domain name pointing, redirection or cloaking.
Your next decision is what extension you want, as in, co.uk or .com or .biz. Your choice will largely depend of course on where your customers are and also who you want to attract to your site.