Dubai is like Las Vegas without the sex and the drugs. So it's Las Vegas without a point.
The sandy, resource-less and charmless Emirate of Dubai is on the verge of bankruptcy. You probably all heard about it but in summary here's what's wrong with Dubai:
1) Unlike what you may think, Dubai has no oil
2) It has no fiscal savings (big spender)
3) It is highly leveraged, with an estimated debt of US$80-90bn (equivalent to 100% of Dubai's GDP)
4) It just suffered a real estate bubble
Here is how Dubai builds its projects through Dubai World; it creates state-owned companies like Nakheel (the property developer behind projects such as The Palm or The World) issues bonds for several billions of USD and starts building - by exploiting the poor, passport-less, underpaid and suicidal Asian workforce.
Once the project is done, they sell the houses and the apartments and pay back their investors. But when 1) it doesn't sell as well as expected, 2) there's a global economic crisis and 3) there was a real estate bubble in the city - it is hard to get the money to pay back. Dubai has to pay 59bn USD now and asked its creditors if it could postpone the payments until May 2010 (thing that you NEVER EVER do in finance, that was bad PR).
I personally don't care much for Dubai because they clearly deserved it (except my friends and family who's livelihood depend on Dubai's economy, I care for you...but wait, does that mean that I won't get any Christmas gifts from you?!) and what I care about is that other countries learn the lesson. In particular Lebanon with its dumbass Cedar Island project.
If the arguments of it being dumb, stupid, ugly, environmentally destructive, useless and horrible are not enough, then maybe Dubai's failure in The Palm and The World will be convincing enough.
Don't do it!