Going through what I can see:
Unit Frames:
X-Perl Unit Frames (Responsible for the ~AGGRO~ in the middle of the screen as well)
Cast bar:
Quartz
Artwork AddOn:
KGPanels (With imported artwork)
Threat Meter:
Omen Threat Meter
Damage Meter:
Recount
Top information bar: FuBar (Abandoned) I'd recommend using a LibDataBroker bar such as
Bazooka. There are plenty others though.
Chat: Most likely
Prat 3.0
Minimap: Looks like
Sexymap with a custom skin set up
Bars: Most likely a generic bar addon like
Bartender4 or
Dominos, with ButtonFacade (now
Masque Thanks AcidWeb)
Scrolling battle text: Probably
MikScrollingBattleText
Raid Frames:
Grid
Nameplates:
Tidy Plates with
ThreatPlates
DoT Timers above target frame:
ForteXorcist (Thanks Xus)