Man, are you gonna get a lot of different opinions
Best bet is go down to the LHS and see what grabs your fancy. Get what you think you will like, not what the rest of us think you should get.
My 2 cents: If you like detail, a kit with an open top would give you this and more. Anything from Tamiya's Wespe, Marder 3 or 3m to Dragon's Nashorn or Hummel for the Germans or the Academy Tiger with interior (although that is not 100% accurate) - Academy's M10, M12 or Hellcat or Tamiya M20 for a low cost OD fix or the Tamiya Dragon Wagon if funds are plenty.
British stuff apart from the Tamiya Cromwell and Centaur are generally older mouldings or not totally accurate (eg, the Academy Achilles and Stuart Honey ) unless you got the money for Accurate Armour or Cromwell models.
The Ruskies don't go in for much detail - mass production tends to keep it plain. Still an M4A2 or Dragon T34/85 or such would still be nice.
Hope you enjoy whatever you choose.