Architecture varies and has blending of different cultures and can maintain separate artistic styling as well. It can be modern or have strong Indian and Islamic influence. Rather I'd say that countries with deep spiritual tendencies and ties have a more ornate sense of Heaven's design. For the U.S.A. this translates into more "modern" looking structures, for Europe it's their cathedrals with Mandala designs in the stained glass (which can be found everywhere in Heaven), and for Eastern and middle Eastern countries it's the symmetry, floral designs, and mandalas.
There is also a central "hub" to Heaven. A giant marketplace where multiple cultures (found here on Earth and some we haven't seen) come together and can be found. A sharing and a blending of colors and flavors and designs.
People also have their "Totum Animals". These are companions to your soul and protect when you;re here on Earth when needed. Most people don't get their totum animal UNTIL they go to Heaven.These animals can "talk" -but it's Tarzan speak in which the basic concepts are spoken but they are not intellectual or conversational. Jesus' animal is a Lion named Aslan that can talk and is very wise. C.S. Lewis was very "in tuned" with things. My animal is a Jaguar and my sister Emily's is an Owl.
Modern Architecture in Heaven tends to be mind-boggling:
Then there's the more "rustic" or classically artistic style of designs often found here on Earth in Mosques.