I'll admit to being something of an Adam Dunn freak. Just try to name another player who's routinely available in the fourth round, yet reliably delivers 100 R, 40 HR and 100 RBIs.
You can't do it, because there isn't one.
Dunn has reached those numbers in three of the last four seasons, and in the one season he didn't, he still gave you 99, 40 and 92. It's his batting average that's an issue. When you draft Dunn, you need to find someone who can offset 540 at bats in the .245-.265 range.
That's not really the point of this post, however. I'm mentioning Dunn because I recently drafted him in a league where the pick was immediately derided, despite the fact that batting average isn't actually a category.
Instead, we use OPS. Dunn happens to rank 22nd among all active players in career OPS (.900). He's pretty much a perfect player in that particular league. There's a decent argument for taking him in the first round.
And this gets me to the larger purpose of the post: know your league settings.
In virtually all custom leagues, default player ranks won't work. In fact, they can lead to atrocious draft picks, and put your team at a massive disadvantage.
Prior to the NFL season, we discussed this issue with reference to a PPR/IDP draft. My team won that league, and it had a lot to do with the fact that not everyone drafted appropriately for the league's configuration. It amazes me how often this happens to veteran fantasy owners who've played the same settings for years.
Bonus coverage: So the first comment makes a fair point. To avoid that trap, go to your pre-draft player rankings, click "Edit My Rankings," and exclude "248. Moon, Jackie."