The best thing about St. George is the LDS Temple.
It is the oldest operating LDS temple, the 3rd one to be built.
It is the first temple to be opened in Utah (most people think it was the Salt Lake City temple, but although it was started first, it took something like 40 years to complete, In the meantime the St. George Temple was built.
There is not a statue of the angel Moroni on top of the building as with most temples because it was built before the tradition started.
I attended the temple on Friday morning and it was a great start to the day :)