Here's a couple I can remember

WOT = Wide Open Throttle
NWB = Newbie/Beginner
NIB = New In Box
RTFM = Read The F... Manual
AFAIC = As Far As I Know
AFAIR = As Far As I Remember
IMAO = In My Arrogant Opinion
JIC = Just In Case
LTNS = Long Time No See
NBD = No Big Deal
NFI = No F.. Idea
NFC = No F.. Clue
OIC = Oh, I See
OMG = Oh, My God
SH = Sh#t Happens
POS = Piece of Sh#t

and...

AAAAA = American Association Against Acronym Abuse