If it could be only one, I'd keep my 26.75" Weber kettle and put Craycort cast iron in it. If I could pick any one cooker I don't own, it'd probably be a Weber performer or maybe one of the large kamados like a Big Joe.
I have a very hard time imagining life without a Weber kettle, no matter what the replacement would be.
~ Scott ~
Blue Weber Performer + Craycort CI • Brick Red Weber One-Touch Platinum • Weber 26.75 Kettle • Akorn Kamado • ET 732 • Record-crushing ORANGE Thermapen • UDS In Progress