I could give you my top 5 beers of different styles, but all time top 5 or how about breweries?
English Beers
Timothy Taylors Landlord Strong Pale Ale (Classic no nonsense traditional pale ale)
Samuel Smiths Oatmeal Stout (again Classic no nonsense traditional oatmeal stout) or most things by Samuel Smiths
American Beers
Stones Arrogant Bastard Ale (Simply satisfying well rounded ale) or most things by Stones Brewery
Rogue Ales Chipotle Ale (this will probably be short lived, but its so funky I really Like at the moment) or again most things by Rogue Ales
Belgium Beers
Breckenridge Brewery Three Philosophers Quadrupel (this is actually an american brewery but it's Belgium)
or any dark strong Belgium ale of good quality.
Btw not in any particular order