I started off with the Neenah Classic White and have been happy with it. However I recently bought a couple of others that I really like as well if not better; the X-Press It Copic Blending Paper (I agree with Maggie, great to use, a little pricier but worth it), and the Cryogen Iridescent White, just got it and very pretty, gives a subtle sparkle to your work.
I love Gina K's products, however I either got a couple of bad batches of paper, because I tried twice but her white 120 lb. didn't work well for me. The colors weren't the same to blend, so I've saved it for my cards and other mediums. I still love her stuff though....