I am in Doha. People here go all misty eyed whenever Oman is mentioned. I've been, but only as a tourist so can't really comment as far as living there goes, but everyone raves about the people, and the landscape. It has green bits! 
Dubai is like Marmite. There is no doubt it has better shopping and loads more to do and a better infrastructure than here though, but give Doha another 5-10 years and we'll be there, or even better than Dubai. But then the cosiness will be gone. Living in Dubai must feel like living in London - it's very over-populated and anonymous these days - it doesn't seem to have the cosy expat camaraderie anymore.
Abu Dhabi is less brash than Dubai, or at least it was when I went there last - I preferred it.
I would LOVE to go to Beirut. 'Tis on my list. And Jordan, but less of a burning need.
Would never wish to set foot in KSA although I know people who have lived there and loved it. A friend who lived there went back recently and said Jeddah was awful - filthy, noisy, intimidating, the people were horrible, everything was horrible. Riyadh is better I am told.
Bahrain is supposed to be nicer than Doha but I've not been. Doha is very politically stable, which is something to be thankful for.