Well, on the defence points, Turkey has been a member of NATO for years and years and years...they used its offshore waters for american aircraft-carriers during Desert Storm campaign.
Turkey is a wonderful place, the bridge between east and west - Asia Minor as it used to be referred to, and Anatolia before that. However, it is rather split itself in that that it is very heterogenous between north and south, as you might have seen in other countries where there is a strong urban/rural divide.
I think it is a very good thing if Turkey joins the EU: it will 'encourage' better human rights because EU member states are positively discouraged in carrying out torture or the death penalty.
As far as 'fears' that a europe that borders the middle east maybe abhorent to middle-eastern states, it's worth remembering that Yugoslavia, Turkey, Spain, and Albania are all countries which have been muslim AND secular in their recent pasts. However, the religious divide within europe isn't only one of christianity vs. islam...Czechoslovakia, a country I lived 30 km from, divided into 2 nations (Czech and Slovak) in the 1990s along ETHNIC lines - that is, the czechs (allegedly) looked to western europe and the slavs to eastern europe and Russia. If one takes into account Russia as part of europe, as 'eurasia' (and I would argue that the similarity of much of western russia IS very european), then again one has a christian country that has been deeply secular/communist and is itself a reflection of a western tradition (marxism) and thus a movement beyond the liberal/capitalist tripartite europe that 'we' in the UK tend to think of as europe (meaning UK, France, and Germany).
So, one could almost argue that Turkey's wrestle with its secular/islamic divide mirrors the divisions that it faces with europe.
But as I say above, europe has always been a multicultural and multifaith continent.
Of course, Yodhe is right when he points to the function of the EU as one of keeping the peace, and it is a shame that this point tends to be overshadowed in most peoples' minds today - europe tends to be about economic issues - but then again, maybe it means we can move on...
However, I strongly disagree with Blender Bender who writes:
'what happens when you suddenly have a country with such a poor financial history (inflation exceeded 100% a few years ago) joining the already fragile economic balance of the Eurozone?'
Mmmm - given that London is one of the most expensive cities in the world, that the UK has divided into a 2 nations state: those who have and those who don't based on geographical location, and people still refuse to vote for political parties who tax more heavily, it is a bit rich for those in the UK to criticise poorer states. After all, there is still great inequality and degrees of relative poverty in the UK and yet we are supposedly one of the richest countries in the world. So where's it all going to and to whom?