Rogue, in my opinion the "dominoes falling" is coincidence, perhaps spurred on by an unstable Iraq as a neighbor, with ruling powers worried about that instability, but in no way a product of the U.S. invasion in the sense of "a democratic revolution." It's an issue of regime survival, internally.
The Persian Gulf area has been working towards democratic style reform for about 15 years or so. It's a response to internal pressures created by falling GDP per capita. Previously, during the oil boom, the revenue flows were high in real terms, per person. This allowed the Gulf countries to essentially buy off dissenters. It's a very paternalistic, rentier type state.
However, the lack of ability to provide for the people means increased unrest and dissatisfaction with authoritarian governments. Oman and I think either Qatar or maybe UAE instituted a Parliament of sorts in the late 90's. Saudi Arabia recently held elections.
They HAD to to stay in power.
Case in point - guess what issue Iran's government received the most internal criticism for? The Bam earthquake. They were utterly unable to provide disaster relief. That's a serious problem for a soveriegn power, and points out the house of cards to an entire populace.
Lebanon is a totally different issue driven largely by ethnic/sectarian strife. The Syrian influence in Lebanese politics is long standing and entirely corrupt. Methinks the people just got tired of it. Further, while I don't think Syria had anything to do with the bombing, they were blamed for it and the Lebanese were ok with the arrangement provided it was on the down low. However, Syria conducting an attack (perceived, not in actuality) is beyond the pale and embarresses the Lebanese as a nation. It says "WE are in charge and you are not." And that's not something the Lebanese were going to take lying down.
Israel-Palestine also has zero to do with Iraq. Arafat's death finally allowed the process to move forward. He was the single greatest impediment to a solution and anybody who says otherwise doesn't know what the hell they are talking about. There is a REASON Abu Mazen has had to do a bunch of spring cleaning in the PA political and executive machinery. It was full of corrupt old Arafat cronies.
Ironically, IMO, the other major factor is Sharon having the PM spot. It's a sort of "Only Nixon can go to China," situation. However, I should be clear that Israel is a heavily divided nation on the issue. It's not the monolith that everybody seems to want to think. There is no "Israeli position," on the subject. The right wing faction though, is far more inclined to go along with Sharon than a left winger. And since Israel has a proportional representation system, any faction has disproportionate power - if a dissatisfied party leaves the government, that government cannot form a majority and must dissolve, spurring elections. So again, only Sharon could have done this. But Arafat's death was the key. I think that although things could slip backwards there, they're more likely to move forward. Momentum matters.
"In the world of martial arts, respect is often a given. In the real world, it must be earned."
"A stupid man's report of what a clever man says is never accurate because he unconsciously translates what he hears into something he can understand. "--Bertrand Russell
"Liberals - Cosmopolitan critics, men who are the friends of every country save their own. "--Benjamin Disraeli
"A conservative government is an organised hypocrisy."--Benjamin Disraeli