Native WP7 PeopleHub access gives you integrated FB functionality, but if you’re a social media junkie, you’ll need more functionality.
The official Twitter app is highly functional , easy-to use (and free).
Adobe is a must have if you need to read PDFs on the go.
Tag as many songs as you like and find out what’s is playing on the radio. When you figure it out, go directly into the Zune marketplace, hear a 30 second clip, and buy it (or don’t).
Cool app, and goes way beyond the experience available through IE Mobile.
LBS-based service Loopt offers a free app that lets users see where friends are, share their locale and photos.
Watch your DVRed lineup and homeTV from your handset by connecting to Slingbox Solo or Slingbox PRO-HD.
Your smartphone becomes a remote for your media player.
Update your Queu and view instant content if you have a subscription.
WeatherBug is a free, ad-supported weather app: get current conditions, forecasts, radar and maps, and severe weather alerts.
Get the latest and greatest sites, food, drinks, and everything u need for a newly visited locale.
Add to existing WP7’s Xbox LIVE integration with profile editing and messaging features.
Easily see Flickr images that pass through your friends’ Facebook and Windows Live accounts and manage feeds.
Mobile suite of photo effects, fixes, and editing tools.
Take your Web radio app on the go. Other options include iheartradio and Last.fm.
Excellent, basic, easy to read news app.
The best Google Reader app to date for Windows Phone 7.
WP7 does not do flash, but the YouTube app does, so you can view all the cute cat videos you want.