Money can be an excellent graduation gift, and one which your son will certainly have use for. A monetary gift can lessen the financial burdens that college graduates can face, such as rent and car and loan payments. Alternatively, your son could use a monetary gift to purchase a more specialized gift for which he has need, such as a particular type of laptop or camera, or equipment specific to his field of study. Enclosing the money in a nice card or a book that your son will like personalizes the gift.
Some college graduates want to take time off before working full time and prefer to see the world. Giving your son a trip to a destination where he has always wanted to travel can make for a memorable gift. Check with a travel agency to see if there are any package deals including airfare, hotel and local transportation. Enclose the plane tickets and the travel information in a map of the country, or in a guidebook for a fun presentation. Be sure that travel works with your son's plans before purchasing the trip, though; if your son already has a full-time job lined up after graduation, he might not be able to immediately take off the time to travel.
Gift cards and gift certificates provide a way to give a gift that is relevant to your son's personality, while still enabling him to choose the specific items he wants. A gift card to an electronics store allows your son to pick out equipment that he may need, such as a GPS or printer. A gift certificate to a mall or clothing store will enable your son to purchase interview attire or clothing needed for a job. Gas cards can also be a good choice if he has a vehicle and will be commuting to work.
Your son's computer has likely been put through a lot of use during his time in college, so his graduation may be the perfect time to provide him with a new one. Be familiar with your son's wants and needs before you purchase him a computer. Go over specifications such as the operating system, software available, and whether the computer is a laptop or a desktop beforehand to make sure that the computer is appropriate for your son. It might be easiest to present the gift as being an offer to buy your son the computer of his choosing; you and your son can make the trip to the store and purchase the computer together.