What I include in a CL ad depends slightly on the level of bike and who I'm marketing to.

If it's a higher end bike:

Size
parts
year
Any relevant info (condition, issues, repaint, tubulars, etc.)

If it's not high end I might explain what a possible size range might be, who should be interested/why it's the right bike and the above.

I don't want to read the posters creative writing sample when I'm skimming ads. I want quality photos and USEFUL information.

The kind of verbiage that really annoys me is:

Attention collectors! Top of the line! Very desirable!

Collectors know what they should pay attention to - your verbiage is annoying.