I want to give him a gift to show him I love him. But what would be the perfect gift?

How old are you both, what does he do for a living, what does he study in school, or what extra-curriculars does he do?

Does he enjoy music or movies?

I have a lot of ideas but I need a little more information to give you a good one that applies to your boyfriend.

Something which is useful to him. Something which he has planned to lay his hands on for a while but has not had a chance, its even better. For ex. A guitar processor, or some game that he wanted to buy

You need to find out his interests and hobbies.
Example: If he likes Games, buy him a Game.