The Gaza Withdrawal. I've advocated something like this for a long time, mainly because its an inevitability anyways and putting it off is a senseless waste of lives and treasure. Gaza has always been the least valuable and most costly piece of real estate won in the Six-Day War, Yitzhak Rabin used to say that his dream was to wake up one morning and discover that Gaza had fallen into the sea, and, given the demographic realities there, there is simply no way the major settlements well be able to stay there indefinitely. Our presence there also causes serious schisms in the Israeli public, since young students can't figure out why they're being dragged away from their studies to go protect a settlement of five people and a dog in an extremely dangerous area of no strategic value whatsoever. I can see the national/religious attachment to much of Judea and Samaria, especially places like Hebron and Shechem, which have enormous cultural/religious significance and where Jews ought to be allowed to live whatever the political situation there, but there is nothing for us to look for in Gaza, and we ought to get out as soon as possible. There is no reason to spend another dollar or place another soldier in danger there.
That being said, Gaza is a hotbed of terrorism and some kind of Israeli presence will continue there for a long time to come. The key, however, is that it be both military and easily mobile, so it doesn't get us bogged down defending bases and settlements which are easy targets for attack. Gaza can be dealt with militarily, and perhaps more efficiently then it is now, without the presence of settlements.
Where this leaves Arik, though, is another question. He seems to be banking on either a) a national unity government with Labor, or b) his Right wing wont have the guts to walk out of a governing coalition over this issue. I think he's putting all his eggs in one basket in a dangerous way. Labor may refuse to join and the Right will, in my opinion, definitely bolt, which will lead to the government's collapse and new elections. Arik may be thinking that Shas will rejoin the government if the Right bolts but if he thinks that he's crazy. Shas is vindictive the way only religious parties can be and they will never forgive him for bringing their archenemies Shinui into the government.
In short, the decision is excellent strategically, but likely disastrous politically, at least for Sharon. Of course, considering the metastatizing scandals he's been facing, he may be forced out of office fairly soon anyways. If Sharon goes, I strongly doubt that he will be replaced from the Left, the obvious successor is Netanyahu, who will be distinctly less likely to make these type of risky decisions. Sharon may be anticipating something like this, which is why he feels free enough to make some of these serious moves. It may be that, looking his political demise in the face, Arik may have conjured up the sort of fatalistic courage which sometimes afflicts politicians in the twilight of their careers. If a Gaza withdrawal is the result, we can only be grateful for some of stranger vicissitudes of fate.