I obviously do not have the number of dives as many who have commented on this thread do, but here is my 2 cents worth.
I still log every dive, but not in the type of detail that I used to. I no longer have a paper log, but rather, I use an app on my iPad called "Dive Log". I like this app because it is pretty much fill in the blank (and it will auto fill to a degree). It will let you enter all of your equipment and enter JPEGs of your dive (I don't). As for what I typically log, it falls into two broad categories: Things I might need (or find useful) later and things that are unique to this dive.
Normally, I log (some variation of) the following:
Date
Dive site name
Depth & Bottom Time
Water temp & exposure protection
Weights
Visibility (in very general terms: Good, Fair, or Bad)
Did I see something unusual (Was the dive "Sharky? Did I see turtles, dolphins, really interesting landmarks, etc)
If it was a kind of dive I don't do often (I don't do a lot of night dives, so I will note them in my log)
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I have had dive ops want to see my logbook. For instance, IIRC, the Aquacat wanted to see everybody's logbook the first night. Then, they keep track of anybody who hit a "milestone" dive on the trip and they recognized that person/accomplishment at the end of the week.