OK- I just have to reply to this. Not sure why? But seeing as how I started playing in 1981 with 1e I guess I qualify.
It has the real demons from real demonology.
It has a spell to summon some.
To some degree true...but most were in name only and a lot were just invented. For example....Graz'zt, Fraz Urb' Luu. There are no real world equivalents. And the true version of Demogorgon is not a two-headed baboon with tentacles.
It has druids and illusionists as separate classes
even in the spells sections (and the druid is my favorite class).
So does 3e (and so did 2e). Druids are still a separate class (they always have been AFAIK) and illusionists are specialist wizards.
It has a darker and older feel,
even in the way the printing is done,
the pictures look and feel older and
stimulate the imagination more.
While I tend to like the artwork more in 1e than any other edition....to each his own I guess. The "feel" is what you as DM make of it.
3e has three saves. No need for anymore. Need to dodge something? Roll a Reflex save. Need to withstand a physical change or assault? Make a Fortitude save. Need to repel some mind-influencing spell? Make a Will save. Easy, simple, to the point.
It is the original version by the very guy who created RPG
or at least D&D (reason enough?).
Subsequent AD&D and D&D are just copies without the feel.
Possibly true to some degree, but as I said above....the DM is the one that puts the feel into it.
Legends & Lore had pictures in it !!! (duh)
You do mean Deities & Demigods right? The book was recovered near the mid to end of 1e as Legend & Lores, but the original book was called Deities & Demigods.
1st ed Oriental Adventures presented ALL-NEW PC classes
and was written through intensive and passionate research
while 2nd ed Complete Handbooks and I hear Arabian Adventures
only had DISAPPOINTING and NO FUN AT ALL
CHARACTERS KITS which are a real RIP OFF
instead of new PC classes.
The 3e version of OA is a conversion of the original book and then some. The classes are there; the spells, etc. I agree that KITS and the Complete Handbooks were well....garbage (more or less- though I did like the Thieves Handbook). Al-Qadim (the Arabian Adventures stuff) was good, at least IMO.
It has the assassin and the barbarian NOT CHARACTERS KITS.
The barbarian is a core class in the 3e PHB. The Assassin is a prestige class in the DMG. They are both in 3e as good/bad as ever.
Please don't. It seems a lot of what you are saying is #1 based on 2e rather than 1e, and #2 it doesn't seem like you have even seen or looked at 3e at all.
I live in Québec, 80% French-speaking province of Canada and
I've had to order used copies of every AD&D 1st ed book
to individuals in the U.S. cause since we're French here,
less people understand English and the 1st ed had never been
translated in French, as far as I know, so there was no more
copies around even in the used stores but I really wanted
the real one.
Go buy them all before they become an expensive rarity 
I am presently re-reading every book from the 1st ed even if
I'm French though very good in English
and I will NOT play another edition.
I can always take a small thing here and there
from the 2nd edition and add it if I feel the need arise
which I don't till now.
Isn't taking a small thing from here or there and adding it to your game what D&D has ALWAYS been about? You say you will never play another edition? Then you are missing out. While I agree that 2e was bad, 3e is not. It is different, more streamlined, and a lot of fun. It has brought a ton of 1e players back to the game, and if anything can capture that 1e feel it is the new rules.
Hell, look at the 3e DMG and the 1e DMG. The exact same sample scenario is in both books (the dungeon, the scroll tube, the ghouls, etc). It plays just as easily and fun with the 3e rules as it did using the 1e rules.
2e was about storytelling and driving the story. 3e takes the game back to the dungeon, where it should be. It is after all called DUNGEONS & Dragons.
Scott
The Creature Catalog
http://www.enworld.org/cc
Content Editor
Necromancer Games
http://www.necromancergames.com
"Third Edition Rules, First Edition Feel"