I'm a big fan of punctuation. The semi-colon is probably my favorite (followed closely by the parentheses), although you wouldn't know it from the comments I (sporadically, admittedly; my bad) leave on your blogs.
From my comments, there is one clear punctuation prizewinner.
(wait for it)
The exclamation mark!!! Wohooo!! Hells yeah!
Partly this is due to the fact that I am always! so! excited! to finally be catching up on blog reading; however, I suspect my excessive exclamations are mostly due to two other factors:
1. I do a lot of blog reading on Saturday late mornings/early afternoons, after I've had four cups (according to my Mr. Coffee, but really it's just two cups in the world of Actual Coffee Drinkers).
2. I do the rest of my blog reading late at night, so I must! over! compensate! Not that I do this consciously, of course.
What is your favorite?