Which is best? .com, .org, .net, .co.uk
Choosing a domain name with a .co.uk extension (a country-specific domain for the UK) tells people that they’re dealing with a local/UK based entity and is therefore possibly the best option if your business caters for the local community.
If your business would benefit from an international audience then it may be better to get the domain you really want even if it has a different extension. Be aware however that getting your chosen domain but opting for a .ie extension (Irish) may mislead people into believing you only cater for those based in Ireland.
.org and .net are quite acceptable however many people associate a domain name with a .org as being linked to a non-profit making organisation.
There is some argument for choosing a .com domain name in that it could be considered as being more favourable to search engines and where the domain is entered without the relevant extension that a .com may be assumed by the search engine. Our advice would be to consider who your audience is when choosing your domain and maybe secure the .com and the .co.uk and/or alternative domains if available.
If you have just one domain and it’s anything other than the most common .co.uk (assuming you’re UK based and appealing to a UK local audience) then be sure to always refer to and promote your web site and business using the full domain name form.