I bake them without foil and without poking holes. You really don't need to poke the hole, but you DO need to pierce to let the steam escape as soon as it comes out of the oven or it will turn to mush.
I also like to cut them in a large dice, drizzle with olive oil, season as desired (I use S&P and rosemary), and roast them. That is probably my FAVORITE way to eat them. They also make an AWESOME soup!!!
For soup, I like to roast them (about a pound or 2) as above, seasoned only with olive oil, salt and pepper. While they're roasting, I saute onion, garlic, celery, and carrots in a little olive oil (or you can dice up pancetta or a few rashers of bacon, fry until crispy, remove from the pot and reserve, and saute the vegetables in the bacon fat). When the potatoes are done, I throw them in with the vegetables and add about 1.5 - 2 quarts of canned chicken broth, season with thyme (about 2 teaspoons of dried or a TBSP of fresh), S & P to taste, and whatever else you like, and I also throw in some frozen corn -- about a cup. I let it simmer for about 30 minutes and then I puree it. You can add a little milk or cream if you want a smoother, creamier texture but I rarely do that. Then I like to garnish each serving with corn kernels, roasted pistachio nuts, and the crisp bacon bits. YUM!!!