Depends what you call "important". It seems the thread is leaning toward comparable vehicles, so here is my 2 cents worth.
Recce was/is a very important part of battlefield tactics, so you could go a little smaller and a bit more diverse. Seeing as you asked for tanks, say:
Panzer 2 vs BT 7
Panzer 2 Luchs vs M3 or M5
Or you could go Armoured Cars, say:
SdKfz 222 vs BA 20 or M20;
SdKfz 223 vs Staghound ;or
SdKfz 234/2 vs M8 Greyhound
Or go the way of SP Artillery:
Priest or Bishop vs Wespe
Hummel vs M40 (when the kit becomes available)
Centaur IV vs Brummbar (or Sturmtiger for something a little beefier)
You get the idea
Happy Modelling
Peter