Besides Mail, Messaging, Calendar, People, and SkyDrive, Microsoft has also created a few more Modern-style apps for Windows 8. Here's a summary of some of the more prominent ones.
As the name suggests, the Photos app is where you see all your photos. It pulls images from your Pictures library, SkyDrive, Facebook, as well as Filckr accounts. It can also show photos from other devices, such as a network share. It supports searching, sharing, and printing. Except for cropping and rotating, there's not a lot of editing you can do with your photos in this app.
Announced very recently, Xbox Music (via the Music app) is an all-in-one music service with millions of songs which users can stream, download, and own. If you've an Xbox Music Pass, you get unlimited access to songs on your Windows 8 or Windows RT devices, Windows Phone 8 devices, and Xbox 360. Without a paid subscription, free streaming is limited to 10 hours per month after the first six months. Support for Android and iOS devices will come next year. You can also add and playback locally stored music in the Music app.
Similarly, movies you buy in Xbox Video (via the Video app) are available for playback both on Windows 8 and on your Xbox 360. You can also add and playback locally stored videos in the Video app.
Besides discovering and buying games, the Xbox Live Games (via the Games app) allows you to connect and play with friends. You can also create your own gamer avatar.
Bing Maps (via the Maps app) provides location and direction services so that you can find and get to places faster. You can pinpoint locations, get directions, check traffic conditions, and more.
For Web search, you can try the Bing app. A beautifully designed app (apparent when you're searching for images), it supports the Search Charm so that you can initiate a Bing search from anywhere in Windows 8. It works great in snap multi-tasking mode too: with search results displayed in a list on one side and Internet Explorer on the other, you can go through webpages without ever leaving search.
With the Reader app, you can read PDF, XPS, or OXPS documents. You can even highlight and add text annotations on your PDFs. Printing and sharing are also supported. In a nutshell, it's a simple but effective PDF reader for those who don't want to use Adobe Reader.