I read a variety of genres and nonfiction -- as long as I don't read something similar and then jump right into writing, it doesn't effect me. Although if I've been obsessing over a series or genre, I have to cleanse my mental pallet before I work on anything -- usually playing Civ IV does it for me, or reading the news.

I personally use word counts to assess how I'm doing. "Hey, I managed 2K today? Good job self!" Or, "yikes, I've done 50 words in an hour, today obviously isn't going to happen." I don't judge a work by how long it is, though. It's nice to have a word count for work posted online, but only as a way to assess how long it might take me to get through -- for me it's the same as using the thickness of a physical book to judge how long it will take me to read it.