The suicide bomber is the most effective weapon in their arsenal. If it didn't work, they'd try something else. As it is, over 70 suicide (homocide) bomber attacks have successfully killed hundreds of Israelis over the past 21 months.

As this piece from the Times of London points out, these suicide (homocide) attacks aren't acts of desperation.

"Their acts are not expressions of despair or hopelessness, 'cries for help' as the West has come to understand suicide. Nor are they the noble stands of outnumbered warriors, like the Spartans at Thermopylae, or Samson in the Temple. They are the calculated acts of men and women whose ideology celebrates death in a fashion which almost defies Western comprehension. Indeed, these acts are designed to elicit compassion in the West for the killers, a sentiment which the bombers know undermines the West’s capacity to resist barbarism.

The terrorist responsible for the bus bombing which killed 20 Israelis last Wednesday, Mohammed al-Ghoul, was explicit in his motivation. 'How beautiful it is to make my bomb shrapnel kill the enemy,' he wrote immediately before he did just that, 'how beautiful it is to kill and be killed.' These are not the words of one in despair, but on the verge of exultation.

Al-Ghoul was not a wretched, hopeless, outcast but a student pursuing a master’s degree in Islamic studies. His act was not a cry for help but the culminating affirmation of an ideology which holds sway in the Palestinian Authority and other centres of Islamist fundamentalism across the world. It is an ideology inculcated in children from their earliest years."