Those Racing Ralps or Marathon racers are obviously fantastic tyres, but also expensive.
In case you want a cheaper tyre that fits your requirements, get the Schwalbe CX Comp.
I bought mine for 8€ each on a sale and they have been fantastic for the last 2 years.
No flats whatsoever and very versatile. Fast on roads and quite able offroad, just don't use them in actual mud.