If your giftee has all the gadgets to make a killer pizza (if not, see the following slides), give her something handsome to serve it on. At 10.75 inches, this pizza plate from Crate & Barrel ($5.95 each) isn't quite big enough to serve an entire Neapolitan pizza on, but en masse would make great service pieces for a pizza party.
6-Quart Dough-Rising Containers
These dough-rising containers are great for bulk-rising pizza dough or a nice sourdough bread dough. The Cambro buckets pictured here are my favorite ($14 on Amazon) for their ultra-thick sides, but they don't come with lids. I'd go for this set of two 6-quart square containers (with lids) for $24.99 from Amazon. (I prefer square, because they're more space-efficient.)
OXO Kitchen Scale
Does she not have a kitchen scale? If not, this will change her life COMPLETELY. Weighing ingredients for baking takes all the guesswork out of measurement and ensures consistent results from one dough to the next. Which is important when comparing variations in recipes. I use Oxo's 5-Pound Scale with Pull-Out Display, which is nice if you've got a big bowl on top. The one pictured here is $28 from Amazon, but you can also get one with a lighted display for $45.
King Arthur Flour Baking Stone
Is your giftee just starting out? Chances are he'll need a pizza stone. This cordierite stone from King Arthur Flour is large enough to handle a decent size pizza (14.5" by 16.5") and thick enough to absorb and retain heat (half-inch). I prefer rectangular stones to round ones because they're a more forgiving target to hit when placing a pie with your peel. This one is $54.95 from King Arthur
Sicilian Pizza Pan
For the pizza geeks who maybe truly does have it all, I wonder if they'll have some of these. Available in sizes from 6" to 18" square, with some rectangular configurations in between. $17 to $60, from pizzatools.com
A Good Pizza Peel
This one is a bit tricky, because pizza geeks seem to be very particular about their peels. Read J. Kenji Lopez-Alt's guide to pizza peels before proceeding. Your best bet might be the American Metalcraft aluminum peel ($10.95 from cooking.com). If your pizza-maker is a noobie or is working with high-hydration doughs, she might benefit from the Super Peel ($36.95 from Amazon), which is a sort of nonstick conveyor belt for dough.