[Gwaihir the Windlord]

The answer to this is the Eldar (in fact, Fingolfin, there is another thread that talks about this somewhere, but it's good to get another, and probably better one).
Yes, the Elves; they did not really develop their technology, nor would they have wanted to. That is not to say that they are Neanderthal-like (far from it, obviously) but that it was simply against their nature to develop their technology. This for more than one reason, I think.

Firstly and foremost, it is against their nature to wish for change when what they already have is sufficient. Their 'basic' technology they would have found fine. Time-saving things they didn't want, as they dwelled in time and loved it, not to mention that they had an infinite amount of it on their hands, far from wishing to hasten it, I think. Since Elvish civilisations are chiefly made up of the same Elves over a long period of time, rather than the generation pattern of Men, technology advances would probably not have been seen to be required right now -- there was plenty of time. This is a kind of 'time-bubble' mentality. I haven't said that quite right, but you may understand me.
Second, there is the probability that such things as machines, guns or computers would seem abhorrent to an Elda. The Eldar are the closest to the Earth of the two Kindreds; the technology they had -- which they made beautiful, and had high civilisations that did not require machines -- was part of this. Machines are alien to Earth, and are wholly unnatural except that they have come from the human mind. They distance us from the Earth and the laws that it follows, which the Eldar feel they are wholly part of. Again, I am not sure that I have said this in entirely the right way, but again, you can probably get the jist. As an example, if you have any knowledge of the people I am talking about, the 'Aborigine' natives of Australia -- now almost totally displaced by the modern, white settlers of the country -- provide an interesting paralell. Their technology, at the time of British settlement, was far less than that of the Eldar; it was stone age. They had been living like that for, it is thought, perhaps even over forty thousand years almost devoid of change. The reason they were so easily displaced by settlers is because of a massive culture clash. The settlers, of course, Westerners, had the idea of 'land ownership' that we do; it is owned, i.e. 'this is my land.' Which is what the settlers said to the Aborigines, normally along with 'get off it'. The problem was that the Aborigine idea is completely different. The land was not to be owned -- rather, it owned them, and they were part of it, in the same way as were the rocks, the plants and the birds. It is interesting, but when you think about it that is really the natural state of Man, a state that our advancement has distanced us from. Perhaps it is the other way around. If you can bring this concept around back to what I was saying about the Eldar, it shows a lot (it isn't quite the same, but shares a similar principle).
Thirdly, of course, there is the fact that machines and machine-driven civilisation takes over the landscape almost totally, so that it is no longer Earth but a false environment of Man's creation. An Elf would certainly not wish for this type of civilisation.

Up until the Fourth Age, societies were predominantly either Elvish, or closely tied to the Elvish model. The First Age, of course, was dominated by the Elves; the Second Age by Elves and by Numenor, which was an Eldarin-type society; and the Third Age, which was still largely moved by Elves and Elvish-imbued Numenoreans or other Men, that shared the Elvish model of civilisation. The Haradrim, of course, were just barbaric. They had not developed either, but they were, I think, a newer society as well. Either way, it was not until the Fourth Age that we Men came into our own, and started on the drive towards technological greatness. Lamentable in a way, perhaps, but I think that's the way of things.
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