Day 3 for me and I'm more impressed now! I'm still most impressed with the news and reading apps, but here is a list of the apps I am using right now:
News
MyCongress - keep up with your representatives
AP News - Associated Press probably has done the best job of the free iPad news apps
USA Today - my favorite "newspaper" app. It handles just like a newspaper - very cool
Editors' Choice - New York Times. Very light and good for larger stories. I like the editorials, but that is the only thing they have over any other newspaper app
BBC News - a little buggy, but has videos to go along with each story
WSJ - Wall Street Journal. Was so buggy I had to uninstall it. I couldn't even get it to launch.
Eyewitness - Guardian News' feeds of today's top photographs - phenomenal imagery with tips for photographers. However, the images are so good anyone will want this app.
Entertainment
*Netflix - can't believe Apple let them in because they're a competitor, but I'm damn glad they're here! Really great!!!!
Marvel - yep, comics. I can't believe I'm reading them again, but I can't believe how amazing they are on the iPad.
Pandora - much like the iPhone app except bigger.
Yahoo entertainment - very nice job. Updates TV listings, streams some TV shows, and has a fun entertainment news portion.
IMDb - Movie database. Is nice on the iPhone too.
Weather
Weatherbug - definitely my favorite way to view the weather now. It is really fantastic!
AccuWeather - I like what they did, but it is just "too cool" for everyday use. Weatherbug definitely gets the job done better.
Productivity
Adobe Ideas - it was free. It let's you doodle. I just haven't ponied up the $9.99 for Brushes yet.
Kayak Flights - damn cool way to book and track travel! They did a great job.
Calculator XL - ya gotta have a calculator sometimes. It was free.
Evernote - great app on the iPhone and now the iPad. It is basically a bigger version of the iPhone's right now. Voice memos, photo memos, note pad, etc - just a great way to keep track of things.
....most of the other apps in the category come with a bit of a price tag, so I haven't messed with them yet.
Social Media
Wordpress - BIG! Beats the hell out of writing articles on the iPhone.
TweetDeck - was so buggy I uninstalled it. However, I replaced it with.....
Twitterrific - holy crap has this made Twitter awesome again! You have not enjoyed twitter until you've tweeted from this app! It is almost worth buying an iPad just for this if you're a twitter-holic.
Other
iBooks - you've seen the advertisements. It works just like that. I wish I could transfer my whole paper-book library to this one.
*Air Mouse Pro - this is a slick app for the Touch or iPhone and it got slicker on the iPad. You control your other computers through it. Not VPN or virtual desktop - think of it as a keyboard and mouse for presentations or a home entertainment center remote control (what I use it for)
*1Password - if you have a Mac you should buy this product for your Mac immediately. I feel so sorry for you PC people who don't get this amazing software. If you're going to buy the iPhone/iPad app, be sure to get Pro so you only pay for it one time.
Zillow - holy crap is this not a real estate agent or home shopper's dream come true. Even if you aren't in the market to buy a house, get this app - it is just awesome....and free.
WTD - and of course....the crack machine game found in most bars across America. No longer do you need to turn a $5 into quarters for good drunken fun, you can get it for free on the iPad now. It is the game where you tell it which picture is missing what. If you have no idea what I'm talking about, then you need to get out more. This is the one video game women will play in public for hours on end.
*denotes this application is not free. Netflix is free, but requires subscription to their service.