Ummmmm... maybe it's just me.. but wasn't the OP's question actually "one saw for the rest of your life"?
A lot of answers seem to be more answering "favourite saw (s)".. Not "one saw for the rest of your life?"
Truly, that answer would really depend on your age. My answer 20 years ago would, obviously, different than my answer now.
How about .. "what was your favourite saw 20 years ago" .. What's your favourite saw now.., or,... Which of your collection would you keep, if you could keep only one?"
While I've got the keyboard out and the time to type, lemme tell you about the one saw that I was glad to get rid of.. One night, at work ( I worked in a bar at the time), a customer walks up to me at the door, and asks me if I wanted to buy a chainsaw.. What an 'effin random thing to be asked!! He said his credit card had been declined, and he wanted another couple of beers.. He said the chainsaw could be mine for the whopping sum of $20.00 ( CDN) .. Maybe, I said.. let's see it! Truly, I don't remember what even brand it was. He calls me outside the door, and damn if he doesn't fire it up in the parking lot.. LMFAO. Security lost their minds , and I told him I'd take it, just to get him to shut it off. So, $20.00 later, I've got a chain saw in my trunk, and he's got enough cash for 3 more beers.
Well, the saw ran fine.. mostly.. but it was hit and miss. It'd start, and run like a champ, and then, it was a crap shoot on whether or not it would re-start. It was frustration on a scale I'd never experienced. I eventually figured out that it was probably bad crank seals. At that time, I didn't know how to diagnose that. They may leak a bit, and still start cold, but you can't count on enough vacuum to draw enough mixture through the carb for proper atomization to start when hot.
In front of my suburban house, there was a tree that we called the "magic tree". If you left something under it, it would usually disappear by the next day.. Finally .. one day.. The 'effin thing started, worked, and then refused to re-start.. I threw it under the magic tree, and then went inside. From my living room couch, I could see the magic tree. I cracked a cold one, and sat back and watched..
It wasn't even 20 minutes later, when someone pulled up in a pick up truck, and stopped just a few feet past the magic tree. He got out, and did the classic .. look right .. look left.. look around a bit more.. and then ran over .. grabbed the saw, tossed it in the back of the pick up.. he ran back to the cab, jumped in and then left like his ass was on fire.. I was sitting on my couch, watching leave with what he thought was the score of the decade. I was almost pissing myself..
I figured .. "Karma is a *****".. He thought that he was stealing a saw left out by a home owner by mistake.. He thought that he was the winner.. LOL.
In my mind.. I wondered how much aggravation that that saw had cost him.
Saw I'd say was the last saw for me ever? .. One thing..
Saw I'd say was ever the saw that I'm so 'effin glad I got rid of? Another thing entirely!!