Well I've had mine for about two weeks now and this is what I've been doing with it:
Twitter - light socialization, sharing links I enjoy.
iPhoto - general image editing, a pretty powerful app for mobile.
Storehouse - Interesting platform to consume new content. Beautiful layout with short video integration. Heavy on visual storytelling. Also features content production options and plugs into services like Flickr.
BikeMap - GPS capable app that excels at providing map functionality offline. Easy to plan and discover new bike routes with terrain specific options.
Free WiFi - Nice app that has offline map features allowing you to discover public WiFi to save on data. Most locations are reliable in my experience.
Drippler - News discovery app that analyzes your device and provides news and information surrounding iOS. Easy way to locate daily freebies (apps).
Hangouts - Provides VoIP integration for Google Voice over Wi-Fi and data 3G or better. Place and easily receive calls. SMS integration coming soon. I'd like to use this app for socialization more than I do but I don't know very many people that make use of it.
Skype - My go-to messenger most of the time. Decent video and voice calling.
Pocket - Frequently save articles for offline viewing. Great night viewing layout. Evernote integration.
Feedly - Good news discovery app with options to subscribe to popular feeds listed categorically with the ability to send articles to Pocket.
Flipboard - I mainly use this app to plug into my Twitter. Provides easy and quick card style navigation of shared links. It also makes viewing content shared on Twitter lists a breeze. Very easy to send articles to Pocket. Only drawback is the lack of a night viewing mode.
Evernote - I mainly use this to compile interest specific notebooks. For example if I find something interesting on camping it ends up in Pocket, then I'll send it to a notebook of mine designed around collecting ideas for camping or travel. Very useful for organizing ideas.
Wider Image - Reuters app that is based around photojournalism. Heavy on visual content and reporting, more so than Storehouse. Has a cool map that allows you to pick an area in the world and explore the stories around it. Ability to follow your favorite photojournalists.
FullControl - Nice little app that allows you to control your Mac from a couch or wherever. Trackpad, keyboard, and shortcut integration. Most useful if you're using a decent display or a TV.
WakeUp Pro - I use this to wake up every morning to my own music, requires me complete a math problem before turning off. Apparently this activates areas of the brain to ensure you are fully awake. I've found it generally works well.
Thermometer - Nice little app that provides a variety of weather conditions as well as comfort level.
For cloud services I'm fairly platform agnostic, making use of ADrive, OneDrive, Dropbox, and Google Drive. Flickr mainly for photo storage and the free terabyte of space. There's a number of apps I didn't mention here but I definitely have a decent share of mobile games and a few streaming apps like Spotify and Rdio. I mainly just use my MacBook for work now. iPad for everything else. The separation actually seems to help me stay focused.