Instapaper Pro [$4.99]
Basically lets you save webpage for later offline reading, optimized for the iPad's screen with all the crapola and ads removed, hyperlinks intact. If you like to read articles online, this app is for you.
Sketchbook Pro [$7.99], Brushes [$9.99]
These are the programs I use to draw with my thumb while sitting in the bathtub. Speaking of which, I need to get a bigger freezer bag for my iPad so I don't get bubbles on it. Outline your drawing in Sketchbook Pro, export it to Photos, import to Brushes for some color, save it, then pop it open in PS Mobile for some effects or tweaks. Awesome.
If you ask the programming elite the iPad will squelch the young would-be hackers of the world because you can't open it up and mess with it. That a whole generation of programers died with the iPad's introduction. iChalkboard is a really charming sketch app that looks and sounds like a real chalkboard with colored chalk... made by a 13 year old kid. I'd like to say I bought this app to spite the dusty quintessential nerds who like coding with a 30 year old programing language and perpetuating fifteen year old media formats... but it actually does look pretty cool!
Best word processing software I've ever used, hands down, except no substitutes. The iPad version from everything I've seen rocks rockstar socks.
Weatherbug Elite [$4.99]
If you have and like viewing Weather on your iPod Touch or iPhone and you're miffed it isn't on the iPad. Get this app, it looks stunning, complete with satellite topography, forecasts, the works.
Things for iPad [$19.99]
The most expensive app I bought. It's a project organizer, kinda like a super to-do list but without any of the bullcrap most of the other 2do apps I've seen have. It's elegant, customizable, and simple to use from all the screenshots I've seen.
Shakespeare Pro [$4.99]
All of his plays, sonnets, and writings stuck inside a mini search engine with portraits, information, and kids book versions of the plays. Lizzy squealed with glee when she saw it so I bought it.
Basically what it says, specifically for apps and web content. I've been using iWeb as a mock up for the website I want to develop, but it's really limited and Dreamweaver doesn't let you conceptualize a project quickly. If you're even dabbling in web design or making your own apps, take a big fat look at iMockups
In the free or nearly free range I also picked up:
BBC News, Bloomberg for iPad, eBay for iPad, iBooks, NBA Game Timer, Netflix, NPR for iPad, Voice Memos, The Wall Street Journal, Pandora, IDW Transformers Comics, and Marvel Comics... just so I could spitefully delete it later.
Update: I caved and got Real Racer HD [$9.99] just because I love driving games.