Around here (NC) pumpkins can be found on every street corner in September and October. I bought mine at the Farmer's Market and they were delicious... well mostly. I bought four, so let me explain. The first two I bought in late September at the same time. I had been eyeing the pumpkins and wanting to get one but it had been so warm in the previous days I wasn't in the mood. Finally it turned cooler and I decided to go for it. I chose two medium-large pumpkins that looked good and took them home to cook. Turns out they were delicious! Nothing "special" about them.
The next time I went to the Farmer's Market I was a little over confident in my ability to choose a good pumpkin. I grabbed one that looked similiar to the previous ones and headed home. I excitedly cooked it, only to discover it was stringy and tasteless. I could have made pie with it but it would have required a ton of spices and sugar to achieve a mediocre pie.
The final time I bought my pumpkin I decided to ask. They recommended one that was a medium size. I took it home, cooked it, and it turned out to be as good as the first two.
I still have no idea how to choose a tasty pumpkin, but I do know that some will make delicious soups and pies with little else needed, while others will be stringy and flavorless. My only advice is to ask, and if your first one turns out to be a dud, don't give up hope.
I did google something to the effect of "Can I eat all pumpkins?" to make sure I didn't buy one that was inedible. The results were very conflicting. Some sites saying you can ONLY eat pie pumpkins and other sites saying a pumpkin is a pumpkin. I decided to ask the closest thing I know to a pumpkin expert - the lady selling the pumpkins at the Farmer's Market. She said that all pumpkins are edible and can be used in recipes, some just might be sweeter and less stringy than others.
Use this pumpkin puree recipe to get your pumpkin ready for delicious pumpkin recipes. The pictures are actually from the one "dud" pumpkin that was less flavorful, so you might notice the pumpkin is a little less colorful. However, the process is the same so just hope yours turns out better than this one. Happy pumpkin hunting!