It's a tough question to answer. There are two ways to value a grill. First would be the one most valuable to cook on. The other would be value in terms of being a collectible. There is probably some overlap between the two but it is unlikely to be very high. The cooker vs. looker classification.
Then among the cookers, there can be further criteria. Is the most versatile one the most valuable? Perhaps the cooker that does one thing very well warrants the most prized selection.
On the first account, my selection goes to cookers. In theory all of mine are cookers though there are some I have not used in years. Among the most versatile cookers, I would have to put my 26 at the top of the list. It's large enough to do a turkey or full leg of lamb or a couple racks of beef ribs. Though I haven't smoked on mine, other members here have demonstrated that capability. When it comes to doing one thing extremely well, my choice is my 18.5 WSM.
With that thought in mind, I'll deviate from the rules and post two pictures. First is my 26. If I had to reduce the count to a single grill, this would be the one.
Were I to select the Weber that produces hands down my favorite food - BBQ - I'd go with my 18.5 WSM (pictured here with it's siblings.
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