Things to Make and Do in the Fourth Dimension and The Magic of Math.
All three books present themselves to a public with not much math background, but they go about it in different ways. One of the most obvious differences is that The Joy of X (which I'll call Joy from now on) is split into a whole bunch of little chapters of about eight pages. These go through the general topics of arithmetic, algebra, geometry, calculus, statistics, and some other newer ideas in mathematics, in that order.
It is also full of personal anecdotes, which makes the reading more memorable. Things to Make and Do in the Fourth Dimension (which I'll call 4D) had a few anecdotes, and a lot of little activities for you to do yourself, which made it very fun to read. The Magic of Math (Magic) did not have many anecdotes or activities. But, it did have proofs, which 4D lacked and Joy only did a few of.
Of the three books, 4D gives the best impression of an actual tour, guiding the reader through whole areas of mathematics and stopping to marvel at each one. In comparison, Magic seems a bit laid back, with only 12 chapters (4D has 21), but you can really take your time to understand the subjects you're given. As I said before, Joy has short chapters. It is therefore more fast-paced, a whirlwind of "Look at that! Isn't that cool? Now, on to the next thing!"
Personally, I think 4D is the best of the three, with Magic as the second and Joy bringing up the rear. This is not to say that Joy is bad. If you like the style of bite-sized tidbits of math, it will probably be your favorite. You can come to your own conclusion, and pick which book (or books) you want to read.