As of 2.1, CiviEvent allows admins to define which status(es) are "counted" as registered and which are not. The CiviEvent Dashboard - Event Summary includes links listings (forced search) of participants in both "buckets" (the counted and not-counted buckets) in the "Participants" column.
I've made those links more prominent, and added a link (to view all participants) to the Event Title column in the "Manage Events" listings and the contact Events tab listing.
Default "counted" statuses: Registered, Attended
Default "not-counted": No-show, Cancelled, Pending
The URL pattern to force a search with "counted" statuses is: civicrm/event/search?force=1&reset=1&event=$eventID&status=true
(status=false will list "not-counted" participants, omit status param to list all participants regardless of status)
— Original post from Brian Choc ----
When managing an event, there is a link to a Public Participant listing. This is OK, but what would be very helpful would be a second link to a (nonpublic) proper Participant List with View/Edit options. Especially when one manages multiple events on the same day or with the same name, a query-by-ID would be exceptionally helpful.