Help buying a track (or two)

I want some help buying a few tracks.
These 8 tracks is the only ones I dont own.
But Im a guy who hate to buy cars/tracks/paints I dont use regularly.
I recently saw in another thread someone who was absolutely in love with Knutstorp Ring(if I recall right).

Question: If I only want to buy 1 or 2 tracks which one(s) should it be?

ByTheWay: Dont tell me to buy all of them - just because. But Im open for well argumented proposal(s) - if you really think there is a must have...

Help buying a track (or two)