I have been racing at quite a lot of circuits during the years. But I will share my 3 favourites.
1. Brno, Czech RepublicBrno is in many ways forgotten since it has not hosted F1. But it is a truly fantastic circuit. It has got all of that you get from circuits like Spa, Monza and classic european circuits.
The track winds through close to the trees in the woods outside of beautiful Brno city. the track is wide and many fast flowing corners with wide kerbs you really can push the limit on. the elevation changes are breathtaking just like Spa, and it also has a golf course within it's circumference like Monza.
There is no asphalt run-off wich gives it it's old school feeling. A truly fantastic circuit!
2. Sachsenring, GermanyJust like Brno this track is located at the hilly countryside so it features lots of elevation changes. It has THAT downhill slope before the penultimate corner that you take a breath every time you enter, it's almost terrifying!
The first and middle part of the track is really flowing and fast. A great circuit just like Brno.
3. Salzburgring, AustriaA speed-freaks circuit located at the foot between two mountains outside Salzburg. A great circuit with one of the fastest corners in europe just after the long 1,4km backstraight. Many trackdays are organized here and i recommend everyone to visit.
Honorary mention: Knutstorp, SwedenMy favourite track in my home country. lots of elevation changes and often named the Nordschleife of Sweden, even though it's only 2,3km short