A nice pair of jeans, head phones or video games and sports memorabilia of favorite teams tend to be safe options when deciding on a gift for your 25 year old boyfriend. Also, consider your budget along with his interests and how long you have been in a relationship.
When deciding on the perfect gift, don't spend more than you can just to impress the guy; he will love it because you're the one giving it to him. Instead, try to come up with the best product for your money. Check Amazon for a lower price or retailmenot.com for coupons and discounts on your chosen items. When it comes down to choosing the actual gift, think about what he likes to do and where his interests lie, then type "(interest), gift" on Pinterest.com for a list of ideas.
Consider how long you have been together. For most couples, it would be rather inappropriate to get a boyfriend of 3 months an expensive watch. Likewise, it would also be awkward to gift a boyfriend of 3 years with just a card. The longer you have been together, the more flexibility you have. For newer relationships, consider taking your boyfriend to a nice sit down restaurant and giving him a book relating to one of his interests.