After weeks of hard testing, fixing, re-testing, and fixing even more, the 1.5 Pre-Release is now ready for testing! We are in the final stretch for 1.5, and while it has taken a little longer than many expected, there is a silver lining! Tons of features were added for the Redstone Update, and a landslide of bugs were swept away, to make sure the final release was as smooth and easy as possible.

Ready to see a feature list this time, instead of just bug fixes? Here you go!

1.5 Pre-Release Features:

• Added Redstone Comparator (used in Redstone logic)
• Added Hopper (collects items and moves them to containers)
• Added Dropper (similar to Dispensers, but always drops the item)
• Added Activator Rail (activates TNT Minecarts)
• Added Daylight Sensor
• Added Trapped Chest
• Added Weighed Pressure Plate
• Added Block of Redstone
• Added Nether Brick (item)
• Added Nether Quartz and ore
• Added Block of Quartz, with half blocks and chiseled variants
• New command: /scoreboard
• New command: /effect
• Containers and mobs can have custom names
• Inventory management has been changed, for example you can drag-place items over slots
• Texture packs now have separate images for each block and item, and can have animations
• Nether Quartz Ore now spawns in the Nether
• Smooth lighting now has three settings (none, minimal, maximum)
• More detailed death messages
• Some hostile mobs now are harder in Hard difficulty
  Many, many, bug fixes
• Removed Herobrine

via 1.5 Pre-Release (Finally) Ready For Testing! – Minecraft Forum.