I love the mesh tool in Illustrator for the realistic effects you can create. The thumbnail at the lower left shows the complexity of the mesh for this illustration.

This fountain pen was created in Illustrator using layered gradient fills.

Another fountain pen created in Illustrator for those who prefer gold.

These pearls were created in Illustrator using the mesh tool, gradient fills and textures.

Character illustration for a graphic novel, created in Illustrator.

This swashbuckling pirate was created in Illustrator as an illustration for a children's book.

This frustrated feline was created in Illustrator as an illustration for a children's book.