Here is the recommended Ping List for Wordpress. You have Smart Update Pinger installed to ensure only post published posts get pinged.

http://blogsearch.google.com/ping/RPC2
http://api.feedster.com/ping
http://api.moreover.com/ping
http://api.moreover.com/RPC2
http://blog.goo.ne.jp/XMLRPC
http://blogdb.jp/xmlrpc/
http://coreblog.org/ping/
http://ping.blo.gs/
http://ping.bloggers.jp/rpc/
http://ping.cocolog-nifty.com/xmlrpc
http://ping.syndic8.com/xmlrpc.php
http://ping.weblogalot.com/rpc.php
http://pinger.blogflux.com/rpc
http://rpc.blogrolling.com/pinger/
http://rpc.icerocket.com:10080/
http://rpc.pingomatic.com/
http://rpc.technorati.com/rpc/ping
http://rpc.weblogs.com/RPC2
http://topicexchange.com/RPC2
http://www.blogdigger.com/RPC2
http://xping.pubsub.com/ping
http://api.my.yahoo.com/rss/ping