Check out this article on the false, multi-culti belief in a great Islamic civilization from Front Page; the author has the facts right and his conclusion is, sadly, quite correct, with the partial exception of Muslim Spain, which was actually a pretty decent place between about 750 and 1000 AD..

Antonio says that the majesty of Islamic civilization is stressed in Spanish schools, or at least was when he was there; he thinks the real reason is that Spain was conquered by the Muslims from the Christians and then reconquered by the Christians after a war that lasted, on and off, for almost eight hundred years. Spain and Christianity look quite heroic as the vanquishers of such a powerful and rich culture, so said culture's real level of power and wealth tends to be inflated.. Also, several of the finer moments in Muslim history did occur in tradition-rich Córdoba under the Umayyad Emirate, which continued holding power in Muslim Spain long after the Abbasids had overthrown them (750 AD) in the rest of the Muslim world. Islamic Spain was thus politically independent of the rest of the Muslim world, the only independent Muslim state outside the Baghdad Caliphate, and it shouldn't be a surprise that Muslim rule in Spain was different from Muslim rule across the Straits. Spanish Islam under the Umayyads was rather tolerant, the emirs and later caliphs established a functioning government and promoted agriculture and commerce, and Córdoba was genuinely cosmopolitan. This generally happy state of affairs crashed after the death of Almanzor in 1002, when Islamic Spain broke up into tiny warlord states which were rather similar to the feudal duchies and counties of Christian Europe. Everything in Islamic Spain then proceeded to go straight to hell and only got worse until the Muslims finally got the boot from their last little enclave in 1492.

The Spaniards quite reasonably feel somewhat proprietary about the accomplishments of Muslim Spain, since the number of foreign Muslims who came to occupy the land that is now Spain was small. Most Spanish Muslims were the same old Celt-Iberian-Roman-Visigothic people who had always lived in Spain who got converted, though there's no question that occupying Muslims left plenty of their genes to be passed down along with those of the folk who had already been there. (Also, the occupying Muslims brought many Slavic and black African slaves to Spain, where they of course reproduced and blended in with the already-existing mix.) There is still a definite tendency in Spain today to distinguish the noble Moors who fought against El Cid from the nasty Moroccans who pick lettuce.

Source: Atlas histórico de España y Portugal.