Position does matter however bridge and neck pickups have different outputs. This is from the Seymour Duncan FAQ:

What's the difference between neck, middle and bridge position pickups?
The difference in bridge vs. neck/middle pickups is their output. There is naturally less volume generated from the bridge pickup due to less string movement the closer the pickup is to the bridge. Bridge pickups are usually wound hotter than neck/middle pickups to compensate for the reduced string movement. This produces an even output between all the pickups.

more at
http://www.seymourduncan.com/website/support/faqdescr.shtml#bridgemiddleneck