.UK or .CO.UK ?

I prefer .uk but I am lazy so its less to type.

Google now see's .uk as a proper extension so I wouldn't worry either way.

Get the .co.uk . It's the standard UK domain name. I have never seen a website that has just .uk.

I prefer co.uk also

As Mickyfu said, I agree that you need a pre-existing .co.uk or one of the other .something.uk extention to get the .uk registered until that date in 2019. My advice if this is the case is to register a .co.uk extension (if you are eligible, it's for UK residents only I think), first, establish a good site, and then within a year or so try to register for the .uk extention. May be a person who knows better will give you a correct advice on this.

Also read this:

~Quote:
New registrations directly under .uk have been accepted by Nominet since 10 June 2014 08:00 BST, however there is a reservation period for existing customers who already have a .co.uk, .org.uk, .me.uk, .net.uk, .ltd.uk or .plc.uk domain to claim the corresponding .uk domain, which runs until 07:59 BST on 10 June 2019
~Unquote.

The clue in above statement is "corresponding" -- do some research on what domainName.uk you need, and may be you can get registered if there isn't any, or if you yourself can register for yourIntendedDomainName.co.uk in coming days, which will enable to get yourIntendedDomainName.uk in future as that will be reserved for you because you have the yourIntendedDomainName.co.uk registered...