We go into some detail for the new 1.8 features, covering each item as it was presented. Take a look!
Some things that were touched on at PAX, regarding 1.8:
Cobwebs, Mineshafts & More
Notch said that randomly generated, abandoned mine shafts would occur in world generation, many of them with the new cobweb blocks scattered throughout. It was said that exploration would yield rewards in locations like the mine shafts, as well as a new type of dungeon, so keep an eye out for that! Furthermore, some of the NPC villages were shown at the demonstration, and while they were currently vacant, the architecture was remarkable for a world-generated town. Very exciting!
Endermen
We were shown a detailed look at the elusive Endermen, where it could be seen how they reacted to the player's presence. If a player looks in their general direction (or otherwise refrains from direct interaction), they remain peaceful. However, looking directly at them (with the cross-hairs on them) causes them to become agitated, teleporting to and attacking the player! It was also said that they could randomly pick up and deposit blocks on a whim, and that they would spawn quite rarely upon release of 1.8.
New Lighting
In addition to the day/night cycle being adjustable, light is generated very differently now. The day/night transition will be very smooth, doing away with the "block by block, row by row" light level changes we have now. Also, objects like torches, light stone etc. will generate their own type (and color) of light, making it much easier to distinguish between them, as well as giving players the ability to light an area how they like! Finally, a new Brightness slider was added, allowing players to set the overall lighting of their game to their personal tastes!
Experience, Hunger
The new Hunger bar will take the place of how food heals players currently. The more filled it is, the faster the player will regenerate health. If it dips too low, health will actually start being lost! Notch showed a new "eating" animation to go with the new system, as well as demonstrating the various types of meat being added (such as beef, and apparently zombie meat).
Experience will be gained by defeating monsters and collecting the "Experience Orbs" they drop, which will later be used to purchase goodies for the player. It was not specified what could be bought at this time, but they assured us that it would be worthwhile.
Rivers, Oceans
Rivers and oceans will now be generated in the world, along with existing biomes. The rivers are quite large, and can either span a length of land with a connection to an ocean, or form a "circular" river, that feeds into itself. It was also said that rivers will not flow at this time, but it was being considered.
Expanded Combat
Bows can now be "charged" longer, for higher damage output. Additionally, it will be possible to get critical hits, either from attacking while coming down from a jump, or semi-randomly from a charged bow shot! New impact animations were shown for monsters as well, including having arrows lodged in the monster being shot. Also, it will be possible to sprint for extended periods, and monsters hit while sprinting will go flying. Quite useful for spiders and creepers!
New (and Expanded) Biomes
Biomes will be much larger than before, with more clearly marked borders between them. We saw the transition from a "plains" type biome into a desert, and the difference was much more noticeable. The desert that was shown was massive, enveloping an area that, currently, would hold anywhere from 2-3 biomes at once! There was some talk of a Mountain biome as well, but we weren't able to see one at this time. Keep an eye out for this!
1.8 will add Creative Mode
Since the Adventure mode will be replacing Survival, Mojang has also re-implemented Creative mode! In this mode, players will take no damage, be able to fly, control day/night directly, can spawn infinite items of any type, and can break blocks with one hit!
1.8 is expected to be released sometime in the next few weeks. Keep an eye out for its release, as well as more update information right here!