I think that some might be surprised to hear how much I sleep and how important it is to me. I average right around eight hours per day (tracked for a few months), and prioritize sleep very strongly, even over most work.
Once ten pm comes around, I have four options for things I'm allowed to do: I can play violin, read a book, work, or sleep. Computer is off at midnight every day, at which point I usually read for an hour or two, and then go to sleep.
There's a concept called hedonic adaptation, which says that we quickly adjust to any increased level of comfort or luxury and cease to appreciate it. Anything good that happens to us becomes our new normal, and we look higher up the ladder, not realizing that we'll quickly adjust to those rungs as well.
The trick, then, is to suppress your hedonic adaptation, while still climbing up that ladder. If you can manage to do that, you can fully appreciate everything you already have, and future accomplishments, acquisitions, etc., will also be fully appreciated.
I don't know if it's fully possible to suppress hedonic adaptation. There's some evidence that zen monks who meditate all the time can do it to a large degree. Even if we're not going to spend all day meditating and will never fully get rid of it, though, we can easily move in that direction.
One strategy I use is to occasionally ask myself, "What's amazing in my life?" For one reason or another, this tends to happen when I'm en route somewhere, either on the subway, walking, or on my motorcycle.