.co like .me is just a balloon that make a lot of money for the registrars but not of that much value for the registrants. Take note that some exotic domain extensions are under different jurisdictions and are not that friendly as .com. For example .ly is domain extension sponsored by Libya Telecom.
Although .co is a country's tld, many people are picking it up just because it is a neat way to indicate a "company". So if you had Rogers Company, and Rogers.com was already taken, you may decide to go for Rogers.co.
It's sort of like sites related to television are picking up the .tv suffix and .me is being used by individuals.
It does make sense to go for the .co if .com and .net and .org are not available AND there are no suitable other-named domains you might want. However, don't do it if your competitor or any related site has the .com suffix, because you can expect people to mistype .co as .com quite often. It is a lesser known suffix, and they may even assume it was just typed wrong.
.co is a bit more expensive than .com. I would register a .org before a .co. The only trouble i have with the .co tld is that it looks like a typo of .com.
You could come up with some clever .co names.
http://www.morewords.com/ends-with/co/ When ever i look for non usual domain name such as .ly, .ru .co, .sy then i do a quick google search for "Words ending in tld", might give you ideas of cool names. .us is the easiest one to find names on, with the above method.
The only trouble i have with the .coWell said Frank.
tld is that it looks like a typo of
Personally I would go with .co only if I can get some "cool" hack like tobac.co , pi.co...
Also you may want to consider adding hyphens in the domain name if you're hell bent for "that" name only.
Seo-wise, wouldn't .co be for Colombia and not for .com-mercial? I'm wonderingt that buying a .co would affect Google rankings since I believe Google likes to favour local markets for local domains? Same with the IP address of the hosting company. I have a feeling .co.uk could rank higher than .com for the UK with the same reputation/content for example, so isn't it better to do what 37 signals do? Just add some suffix like 'now' or 'hq' to the main domain? I'd rather have a .com myself than be favoured for Colombia and lower than general .coms.
The prime example would be http://campfirenow.com