The U.S. Department of State has released it's yearly Country Reports on Terrorism. In this report they sited the following as terrorist organizations:

Abu Nidal Organization (ANO)
Abu Sayyaf Group
Al-Aqsa Martyrs Brigade
Ansar al-Sunnah
Armed Islamic Group (GIA)
Asbat al-Ansar
Aum
Shinrikyo
Basque Fatherland and Liberty (ETA)
Communist Party of
Philippines/New People's Army (CPP/NPA)
Continuity Irish Republican Army
(CIRA)
Gama'a al-Islamiyya (IG)
HAMAS
Harakat ul-Mujahadin (HUM)
Hizballah
Islamic Jihad Group (IJG)
Islamic Movement of Uzbekistan
(IMU)
Jaish-e-Mohammed (JEM)
Jemaah Islamiya Organization (JI)
Al-Jihad
Kahane Chai (Kach)
Kongra-Gel (formerly Kurdistan Worker’s
Party (PKK))
Lashkar e-Tayyiba
Lashkar i Jhangvi (LJ)
Liberation
Tigers of Tamil Eelam (LTTE)
Libyan Islamic Fighting Group (LIFG)
Moroccan Islamic Combatant Group (GICM)
Mujahadin-e Khalq Organization
(MEK)
National Liberation Army (ELN)
Palestine Liberation Front (PLF)
Palestinian Islamic Jihad (PIJ)
Popular Front for the Liberation of
Palestine (PFLP)
Popular Front for the Liberation of Palestine-General
Command (PFLP-GC)
Al-Qa’ida
Al-Qa’ida in Iraq
Al-Qa’ida in the
Islamic Maghreb (AQIM) [Formerly Salafist Group for Call and Combat (GSPC)]
Real IRA (RIRA)
Revolutionary Armed Forces of Colombia (FARC)
Revolutionary Nuclei (RN)
Revolutionary Organization 17 November (17N)
Revolutionary People's Liberation Party/Front (DHKP/C)
Shining Path (SL)
United Self-Defense Forces of Colombia (AUC)