Something you still love and use today? Is there a story behind it?
The post on buying a new wardrobe made me think of this question. Let's leave jewelry out as that obviously is an entirely different category. Also not sure if coats should count, since I have some that are gear and over 15 years old.
Mine is the 11 year old Ralph Lauren dress I wore for my rehearsal dinner. It is a very simple sleeveless blue and black v-neck dress, with a slip and a long chiffon overlayer. It was below-knee length at the time (1999) but I've since had it hemmed and worn it for work countless times. It is so easy to throw on a sweater or blazer on top and be done. The neckline is perfect for me. It does not need ironing. At the time it was the most expensive oiece of clothing I'd ever bought (at $200), including my wedding clothes which came from India.
(I'm not counting the Grateful Dead t-shirt from college that I still wear to sleep - it's 25 years old...).