daniel...from the grocery store...i reckon you just can't go by the kent pumpkin.
also...the butternut is good, and is a different kind of pumpkin so won't cross breed with the kent by accident.
my favouritest, favouritest pumpkin is the spaghetti squash. erica vale seeds carries those (not sold at bunnings over here) and i think also eden seeds has them. the spaghetti squashes can cross with the kents tho...so if you're saving seeds....you have to be deliberate about it. this vine is very long...but also rather, oh, dainty? not the big elephant ear sized leaves. thin leaves, lightish green, very very pretty plant. that will grow up one side of the cage...over the top, and down the other side. you can grow your lettuces in their dappled shade!