When choosing a wedding gift for your son you should consider his lifestyle and his new bride. Even though the gift is for your son, chances are great that he will share the gift with his new bride. Give a gift that is practical yet personal, so that the gift will be used but shows he holds a special place in your heart. Since you will have access to the bridal party, you can ask your son's friends what he might want.
A picnic basket is a practical gift that will be used. Fill it with the necessary utensils for a morning out at the park or beach. Paper plates, cups and napkins can be purchased in fancy patterns so they look less like paper. Choose a nice tablecloth that goes well with the basket, and if your son and his new wife are fond of wine, a nice bottle of their favourite brand would complete the set-up.
If your son and his new wife are religious, a new personalised family Bible is a good gift to choose. If you're not sure about the bride's religion, you can choose a nondenominational Bible so you do not risk offending her. Personalise the Bible by handwriting a personal message to your son wishing him and his new bride happiness in their new marriage.
Gift your son an upgraded genealogy of the new family members, or if genealogy is new to him you can provide a new blank genealogy kit along with a family tree of his family history. Don't worry if you do not have your complete family history. You can supply what you know, and leave it up to the new couple to discover the rest. This will allow the new couple to add the bride's family and any future children.
Weddings are very expensive, and chances are your son will be short on cash after the wedding. If you can afford to do so, it is a nice gesture to offer a gift in the form of cash or in the form of a down payment on a house. You should talk to your son before giving cash. Some couples may feel uncomfortable with accepting cash at their wedding, and according to Emily Post it is in bad taste to specifically ask for cash instead of a wedding gift, so the new couple probably won't ask.