I've taken a lot of great vacations--a month backpacking around the United States with my family (we traveled by train), two weeks visiting Las Vegas and the Canyonlands, two weeks visiting the Netherlands, Paris, and London...
It's really a toss-up between a vacation I took with some girls I'm no longer friends with to Vancouver, BC, a choir tour I took in the 12th grade to San Francisco, and the two week vacation to Vegas and the Canyonlands.
With the first, I spent four days in a city I absolutely love with a chance to explore it on my own and see the things I wanted to see, instead of the things my parents wanted to see. I had a great time. We went out just about every night, even if it was just to go down to the hostel bar, have a beer, and watch the hockey. We met tons of cute Australians and New Zealanders who bought us drinks and made us feel spoiled

We also got to drink lots of great beer
On the choir tour I got to spend an inordinate amount of time with my best friends, who were both in choir with me, and also some of my good guy friends. I clearly remember that the bus trip between Corvallis, OR and San Francisco was the best part of the trip: I ended up curled up with two of my guy friends reading the Weekly World News and receiving alternating back massages from the both of them. Oh, and they were both very, very good-looking. One of them I took to prom. It was a good choice. We also had some great adventures on our own, especially the whole day we spent at Great America.
The trip to the Canyonlands was also a particular favorite. After six days spent in Las Vegas we visited the Grand Canyon, Zion National Park, and Bryce Canyon National Park. I saw the Hoover Dam and Glen Canyon Dam. I also saw Lake Powell before they started lowering it. I would have to say my favorite part of the trip was a morning spent hiking in Zion National Park. We hiked up the Hanging Gardens Trail. To me, it was one of the most beautiful places I have ever seen, and I would really like to go back.
Sometime this summer or fall my honey and I want to take a vacation somewhere. Right now the choices are: roadtrip to California down the Coast to Santa Barbara to visit a friend (which is a good choice because I love Santa Cruz) or a few days spent in Vancouver, BC. We'll see which happens. Both sound good to me!