Hello,
I recently did a survey of 100 Wikimedia projects, to see what their template:welcome and MediaWiki:Welcomecreation messages were like. (MediaWiki:Welcomecreation is the first message new users see when they have successfully registered an account.)
In my opinion, one of the best Welcomecreation messages was Vietnamese Wiktionary's at http://vi.wiktionary.org/wiki/MediaWiki:Welcomecreation .
There is a translation in English here: http://vi.wiktionary.org/wiki/Th%E1%BA%A3o_lu%E1%BA%ADn_MediaWiki:Welcomecre... (the talk page of the previous message)
which could be useful if you want to update the Welcomecreation message for your own wiki.
regards, Brianna user:pfctdayelise