Depends on the veggie. Pumpkins, cabbage, and most root veggies do, but things like cukes, zucchini and tomatos (I find) tend to loose taste.

Any problems making pumpkin pies and preserves out of an Atlantic Giant pumpkin ? Is the flavor good ?

I bought some chunks of giant squash at the farmers market in Fairbanks last fall and it was about the best I've ever had. I look foreward to growing my own this year.
I think birdz n beez is right about the cukes but I've had some very large tomatoes that were good.

Sorry, I should have clarified.
If the plant is labeled giant, then the taste is usually fairly decent to great, as for growing regular veggies to giant size..... that's what I was refering to with tomato and squashes.

Wayne- I have made pies out of AG pumpkins, they taste VERY yummy, so I would think that preserves would work too.

giant tomatoes taste great it is more a matter ripeness, growing conditions, and variety that influnces there taste.

Wow, I'm really looking forward to growing that giant pumpkin. Large, and tasty too. Oh, the anticipation !

Most giant pumpkin growers (or any other giant veggie growers, perhaps) use chemicals on their plants to help ensure success. Always check the labels on the pesticides to make sure the fruit are OK to eat. :-)