As far as large stones, this brand has won the hearts of America's Test Kitchen Baking Stone.
Another thing to consider, especially if you're on a budget, is using an overturned cast iron skillet as a baking stone. Like the stone, it will work for bread and for pizza (just not very large pizzas) and it has the added advantage as working as a skillet! I use my 12" skillet as a baking stone all the time. For use as a baking stone, you need to be sure that it lays flat upside down. I've never seen one that doesn't, but that's something to check, if the handle is at any point higher than the rim of the skillet, it wouldn't lay flat. The skillet works great for pan pizza too. Here's a picture of a recent pan pizza I made in my 12" Lodge cast-iron pan using the Serious Eats Recipe
The skillet will run 20-34 dollars Amazon Skillets. Treat it right and it will be something your great-grandchildren can use. As a matter of fact, mine belonged to my grandmother. I recommend Lodge brand. I didn't know they had this one, I'd buy this before buying a stone 17" Lodge Skillet especially considering the multitasking benefit.
BTW, I have one of those pizza pans as in your first link. It's useless. I keep meaning to throw it away.
EDIT: I need to add a caveat to the idea of the 17" skillet. I just discussed it on Amazon, and I realize that it might not fit in my (or most others') oven. The 12" works great though. If you do end up buying a stone or big skillet, be sure to measure your oven rack first.