I've been meaning to start an iPad apps thread for a while but have been too lazy about it. Here we go...On the Splash screen
(most frequently used)
Atomic Browser (configured with bookmarklets for ReadItLater, ReadItNow (access your ReadItLater list), Readibility, TinyURL, Define highlighted word, Translation for highlighted words, and a link to the Everything (voidtools.com) http server running on my PC <-works brilliantly
Twitbird Pro (I like it for the search/filtering feature)
Photogene (photo editing)
Wordbook XL (The go-to dictionary because it's quick)
Movie Guide (Reviews by Leonard Maltin a.k.a God)
AirVideo (stream movies from wifi, you'll need a PC client running)
FileBrowser (browse files on wifi - mostly used for images)
Wunderlist (To Do app that syncs across devices)
iTap VNC (remote control PC, works great with a multi-mon setup and doesn't log u out like an RDP client would)
Categories...News & Radio
Your favorite news channel probably has an app too (most have live streaming video so it's more convenient having an app, than hitting the site using your browser.)"Social" apps & site specific apps
Target, eBay have apps
Numbers, Pages (official Apple apps, good for editing, creating)
Quickoffice (I've found it to be the fastest app for viewing Office docs)
Merriam Webster Dictionary (the 2nd choice, it has word pronunciations and voice recognition <- (not very reliable))Games & Entertainment
iChess Pack HD (fantastic FICS client)
I had Angry Birds HD but got rid of it coz I realized I was wasting way too much time on it
Shazam (sometimes recognizes songs that SoundHound doesn't)Reference & Misc.
Weather HD (fantastic interface)
Clinometer (handy level app if you want to use your iPad as a cheap spirit level meter)
There are exceptions but for the most part site-specific apps are not worth it, so try the site in your browser before you consider installing an app for it.
For RSS feeds I've found using Google Reader from the browser (rather than getting an RSS app) most convenient. Try this route, unless you have a loathing for Google.
The same applies for ReadItLater, once you have the right bookmarklets installed.