One of the reasons that I shy away from picking 'all time XIs' is that I have seen the difficulties that it has got other people into. 
Here is an example. 
The Royal Mail issued 11 stamps to commemorate the 150th anniversary of the  Football Association. All 4 Nations of the UK were represented. Here is the XI:
Back row: Jimmy Greaves, John Charles, Gordon Banks, George Best, John Barnes.
Front row: Kevin Keegan, Denis Law, Bobby Moore, Bryan Robson, Dave Mackay, Bobby Charlton. 

11 great players- their international careers spanning the years 1950 (John Charles) to 1995 (John Barnes). That's 45 years out of 150 (or 139 years of international football).
There's my first criticism.
Secondly, of course, selection. Here a re a few names to think about: Kenny Dalglish, Ryan Giggs, Stanley Matthews, Dixie Dean, Geoff Hurst, Peter Shilton, Pat Jennings, Cliff Jones, Steve Bloomer, Bob Crompton, Alex James, Cliff Bastin and on and on and on...
Thirdly, a team is not just 11 great players one of whom is a goalkeeper. There's only one defender in the XI, although John Charles was a formidable centre back as well as a centre forward. Brian Clough converted the older Dave Mackay into a sweeper... so at a push we could have a back three of a sweeper and two centre backs... Barnes and Best had many qualities, but they wouldn't be likely to do too much defensive work.