Have used a lot of different combinations, and have observed a lot of different combinations...For chainsaws, the absolute, best, no questions asked saw out there is the Cutters Edge- I forget the model number. It uses a Husqvarna motor, specially "tweaked" for fire dept use, and also has additional air filtration so that the motor does not "choke" in hostile environments. With this, purchase the BULLET chain. The reason the person in the previous post had back luck with the expensive chain is because that model Stihl will not propel a chain fast enough for FD use, hence the thrown teeth. The Cutters Edge saw can do this. Another good chainsaw combo is the Stihl 038 Magnum with the Cutters Edge 12" chain and bar. (Bullet chain again...)
For circular saws, again, no questions- the Partner K700A....Not as big and clumsy as the K-1200, less weight and just slightly less horsepower. The blade- "The Warthog." You will use it once and throw rocks at everything else you have ever used. You will never use anything else again until something better comes out.
Personally, I dont like the Stihl circular saws- WAY too heavy in my opinion. Good luck!!