Similar to BitTorrent trackers. Or are all peers equal in ability and importance?
There is a node that will relay all transactions, regardless of whether a fee is paid:
There are well-connected nodes that are recommended for use by merchants to avoid risk to a race attack. Some of them have inbound connection whitelists so as to lessen the risk of intentional address list poisoning.
The Fallback Nodes can be considered to be "super nodes", as clients will at times use them to get a list of peers. Similarly, any node operated by a mining pool or a major Bitcoin website should similarly be able to provide more accurate information than a regular node (by being connected to much more nodes).