The new Task Manager is one. Hyper-V is ok to me, I use VMware as that works best for my needs.
The new metro apps are pretty interesting. One for example, Custom Tile Maker, can let you put picture tiles and even live picture tiles on the Start Screen. It's a lite version, but lets you use it. If you want more tile patterns, you need to buy it.
Overall efficiency is another thing to write home about. It's like how Windows 7 was fast when it came out after vista, 8 is just even more streamlined.
Using StarDock's Decor8 app, you can customize the crap out of the Start Screen, you can put images and change colors as well.
File Explorer with its Ribbon UI is a dandy feature to use if you like using Ribbon UIs.
The lock screen is also pretty cool, I have a friend that ALWAYS keeps her screen locked because she likes looking at the lock screen.
There are a few other cool things to check out, I'd download the Enterprise 90 day trial as that is the FINAL code as it's the RTM.