This is a remake of my original video:
http://www.youtube.com/watch?v=V0Tbc-ilxvI
It was remade because of people complaining of low quality.

The new update for Minecraft was prereleased by jeb on 9/9/11 and I was testing it out. There was another prerelease update released on 9/13/11. It fixed quite a few bugs. On 9/14/11, 1.8 was officially released. All I noticed that was different was that the Endermen had new purple eyes and purple particles, but that's about it.
1.9 was pre-released on 9/22/11. Has tons of new features, including ACTUAL NPCs! The second pre-release for 1.9 was pre-released on 9/29/11. There are new features that I don't feel like posting, but overall, it's really cool. 1.9 prerelease 3 came out on 10/6/11. This update includes potions, baby animals, and a bunch of other cool stuff. 1.9 prerelease 4 came out on 10/13/11. This update includes stuff like the The End, glistering melons, enchantments, and etc. 1.9 prerelease 5 was released on 10/28/11. It has new achievements, options to turn off clouds, multiple changes to a few textures, and quite a few bug fixes. 1.9 prerelease 6 (hopefully the last one), was released on 11/11/11. It contains "endgame" credits after you defeat the ender dragon, more finished Enderdragon fight, and several blocks being mined faster. Both 1.0 prerelease 1 and prerelease 2 were released on 11/14/11. They include many new features like multiple sound changes (most notably Endermen having a sound), bows degrading (which I don't like at all), and several bugfixes. Notch has stated this will probably be the last one before it's actually released. Minecraft 1.0 was released on 11/18/11 which didn't have much different from the RC2. This is a major milestone for Mojang because they have a (semi)complete game. Congratulations, Notch & Co.! After about 2 months, the crew finally updated the game to 1.1. This update basically included all of the stuff from the weekly prereleases, like mob eggs, nicer transitions, anti-spam on servers, red apples from trees, and language translations. After ANOTHER one and a half months, 1.2 finally got released. In this version, the map height was doubled, a jungle biome, cats, ocelots, and iron golems were, new AIs for mobs, redstone lamps, upside-down slabs and stairs, vine climbing, and much, much more were added. After a long, long wait of about four months, 1.3 was finally released on August 1, 2012.
Update details here:
http://www.minecraftwiki.net/wiki/Version_history#1.3.1
After a mere 2 1/2 months (compared to 1.3), 1.4 was released as the "Pretty Scary Update," just for Halloween.
New features can be viewed here:
http://www.minecraftwiki.net/wiki/Version_history#1.4.2
After four months of heavy testing, 1.5 was released as the "Redstone update," adding a ton of new stuff related to redstone. Details on Wiki:
http://www.minecraftwiki.net/wiki/Version_history#1.5

Weekly pre-releases are planned and their format has the last two digits of the year, for example 2011 is 11, a "w", the week of the year, and an enumerating letter at the end. I will definitely keep updating this video with new links every week, so stay tuned!

Seeds (note that A LOT of these are not working and I need some new ones):
8183605402302361270 (FaroZ06)
-341414797482072298 (Minecraft Wiki, has a stronghold and dungeon in it, may also be outdated)
gimmeabreak (some random video)
666 (kaggletroll) (working)
1.8 1.8 1.8 1.8 1.8 1.8 (FaroZ06)
paper (Aarone2004)
Nether (Aarone2004)
67456438796 (popstick75)
-3674881552751852265 (smash0145) (working)
-132330174258970626 (smash0145) (working)
-2755662514185276883 (Onthebay3636) (working)
000123000456000789 (xXTheNiceIdiotXx) (working)
-8227252585264349741 (TheOrangeWombat) (working)
Derse (deadly180) (working)
Desert (barowenx) (working)
-4297758345965435934 (Reddit) (working)
-5577237764024885427 (Reddit) (working)
Twitch, The Plague Rat (kolopit8) (working)
-8227252585264349741 (MKWiiFunkyKong) (working)
command (DonkeyPuncher1976) (working)
-2089467411 (Reddit) (working)
The houses are pretty intricate and nice for random generation.
Go update now!

If you want 13w03a (improved command blocks, other improvements, dropper block, zombies and skeletons scale to difficulty, mine cart with hopper):
http://assets.minecraft.net/13w03a/minecraft.jar
1a. On Mac, go to (your home folder)/Library/Application Support/minecraft/bin
1b. On Windows 7, go to C:\Users\(Your User Name)\AppData\Roaming\.minecraft\bin
1c. On Windows XP/Vista, go to C:\Documents and Settings\*your user name*\Application Data\.minecraft\bin
2. Back up the original minecraft.jar by copying and pasting it on the desktop or elsewhere.
3. Copy-paste the minecraft.jar you downloaded into the bin folder (make sure it's exactly minecraft.jar or it won't work)
4. Open up Minecraft and enjoy the bugs!