Most people have everything they need, and most of what they want. Buying a gift for such a person's birthday or for Christmas can be very tricky. I'm not a fan of buying clothing for someone else (especially the opposite sex). It's easy to get the size wrong. One garment can have the exact size as another on the tag but try them both on and the fit can be completely different. You need the very person you want to buy it for to be present so that they can try it on. This then eliminates the whole idea of a gift being a surprise. You may as well just give them the money. Perfumes, video games, blu-ray movies and even accessories are always welcome gifts, but they just don't fit the bill when you are trying to show someone that you put some thought behind the present you bought for them.
But here's something you can buy for anybody with a pulse: a book. What's more a book is really a series of thoughts and ideas presented in a coherent piece, therefore any book will make a thoughtful gift by default. Maybe The Book of Secrets by Deepak Chopra for someone who is at sea with themselves; Purple Cow by Seth Godin for someone who is interested in market trends and creating their own; Steven Covey's The Seven Habits of Highly Effective People will not be lost on anyone older than 13; and when it comes to fantasy my all time fiction favourite Charlie and the Chocolate Factory by Roald Dahl will captivate kids and adults alike.
A movie, piece of clothing or perfume can only give limited and temporary benefit to a person. But a well chosen book can have an effect on their entire life.