Based on the evidence...
Ok based on the same amount of evidence that you are using to draw your conclusions, let me propose an alternative sceanrio which meets all of the "facts" at our disposal.
Lets start with the fact that our Hamas "Hero" survived 3 assassinations. Now in the Vietnam war, the US Military Intelligence unit had a saying "Once is an accident, Twice is happenstance, Three times is Enemy Action".
So perhaps our Hamas hero wasnt so much of a "resistance" hero as an israeli/CIA/etc double agent, a very highly ranked double agent. Perhaps someone within the heirarchy of Hamas discovered this. What to do? If you expose him and kill him that will look terrible, one of your most highly ranked generals turning out to be a spy. Thats a great way to forement distrust and is a great way to see your terrorist organisation self implode. (Or perhaps he just ended up on the wrong end of a "cabinet reshuffling" within Hamas...)
So how to turn this to your advantage - hmmm we know he's survived 3 previous "assassination attempts". Well why not let number 4 do the job. So you hire a team of Europeans (Ex-KGB, serb-bosnia, etc. there's bound to be a team or two running around on the Hamas books), make sure they organise to be very obvious (obviously fake passports, passports from dual-Israeli citizens, be caught on CCTV, etc), and have them assassinate your man.
Hamas screams Israel did it, the world media looks at the 3 previous attempts and condemns Mossad without any evidence (why let evidence get in the way of a good conspiracy?), and Israels long standing policy of not commenting either way on assassinations makes it look even guiltier. Job done - a traitor killed, your enemy loses face (and potential friends), and all is happy in terrorist land.
Fits all of the available evidence and explains the obviousness of the hit. But a very different outcome to the knee jerk anti-israeli responses most of you lot are spouting.
Personally, i'll hold of making a decision about who did it until a little thing called "Evidence" comes to light. I know its an outmoded concept in this day and age but you know some of us still believe in Innocent until proven Guilty.
On a side note - I have been mystified by the almost complete disregard that the media has portrayed in following up Hamas's comment that this guy was in Dubai attempting to buy weapons. Considering that there is an almost global ban on selling weapons to Hamas, it would be VERY interesting to know who was looking to do the selling and what weapons they were trying to obtain. I wonder if the Dubai police are spending anytime following this angle, seeing as its their soil being used to conduct illegal weapons sales... Yeah your right im not holding my breath...