B&H Photo Video has a great deal on the Lexar 64GB Professional 1000x UHS-II SDXC (Class 10, UHS Speed Class 3) — it’s only $33.99, save $15 from the regular price of $49.
This is a fast UHS-II card supporting up to 150 MB/s read and 75 MB/s write in cameras with UHS-II interfaces. As of writing, none of the Canon cameras support UHS-II but it never hurts to buy a card that is future-proof in case the next camera will support it! This card is backwards compatible to UHS-I interfaces.