I've heard at several fantasy baseball players proudly state that they ignore Average Draft Position (ADP) when planning for their drafts. The reasoning seems to be that you should 'think for yourself'...which would imply that visiting blogs, websites, and other sources of information isn't a good idea either. Of course, anyone suggesting this is missing the point of ADP data. I'm not reviewing it to figure out which players are the most valuable. I'm reviewing it to see how early I need to pick the players I really like if I don't want to risk having them selected by someone else first. I may think that Carlos Gonzalez is worth a 6th round pick, but ADP data helps me determine that I can wait until the 9th round to get him. Thanks to knowing his ADP, there's a good chance that I can get another 6th round quality player along with Carlos Gonzalez, instead of picking him in the 6th round and getting a 9th round quality player in the 9th round. That's a big edge, and anybody who completely ignores it is almost certainly not drafting as efficiently as they could.
There are several well known sources of ADP data (Mockdraftcentral.com and the newer Couchmanagers.com). I'd also recommend Fantasy Game Day which gathers ADP data from a variety of sources, and provides a spreadsheet that groups players into 'tiers' based on their ADP and average round selected in different sized leagues.