Also, this one-liner might also be a funny mark in the history of LJ:
First poll ever:
Also, I think a page for the semagic client should be done, as it probably is the widest spread client and around since quite some time:
And I think lj_nifty deserves an own page or two or three, too. There have been many, many posts that show suprising little nifty things about livejournal, which are not always documented anywhere else and in between you find lots of fun little programs that somehow interact with your journal.
And because http://www.xkcd.com has a very large fanbase here on lj and because it simply fits, you should really, really, really include this comic: