As far as I know they make no difference at all really unless you want your defualt geo location to be automatic. If you are making a website thats aimed at UK for instance your best of going for a .co.uk domain and hosting on a UK server. But that can always be set in google webmaster tools anyway so no big deal really to be honest.
Well to be truthful, it entirely depends on what kind of a traffic are you hoping to receive on your domain... If you are looking ahead for the search engine traffic, then certainly they both are of equal magnitude...but if you are expecting visitors to type your domain in address bar then for sure the .com extention has a greater weightage...
Yes, all domains have the same value except for country code domain. For example, if your domain is .co.uk then you'll get better result in google.co.uk. Domains like .co, .com, .net, .org, .info, etc are neutral domain. Domains like that will be geo-targeted depends on the server where they are hosted
TLD doesn't count in SEO Only if you target regional rankings a regional tld helps a bit but not very much ...
Yes, Domain name with a country TLD does not plays a major role. if you have a .co.uk domain then its always better to target the UK market rather than US.
Technically there is no difference. but if your website is only for UK visitors then it is better to use .co.uk domain. because .co.uk domain attract more uk visitors