Apps to make iPad function like a computer

I've found sometimes I can't be near a computer and I need to do computery things on my phone, so I've found some apps that help me do certain tasks. Contribute yours too! Cause I'm getting an iPad and I'd like to hear what you use

Documents
Basically a standard file storage app, but free and much more polished than any other under $2 app I've seen. I use this to store audio files and PDFs for later listening/viewing. Also lets you save a webpage to PDF, and you can browse your cloud storage account from within this app. Opens almost any relatively common filetype. Also useful for unzipping files. I have a 1GB Zipped web site in a folder that Documents handles perfectly once unzipped

Duokan reader
I use this for long PDFs, like textbooks. It has a mirrored crop feature that lets you maximize the space on your screen (useful for the iPad mini) and works better/smoother than any other free app I've seen

Signnow
Lets you fill out a PDF form with lots of of text options, then email or export to another app

Quickoffice
Lightweight office suite in one app (unlike iWork) and can easily open documents in other apps (unlike Microsoft office, which is also only for iPhones). Downside is you have to login with Google but it's out of the way, it doesn't interfere. I only do small edits to existing documents in this app so I can't say how good it is for power users but it keeps the fidelity of my XLSX files intact at least

ScannerPro
Lets you take photos of real documents and auto-upload the PDF scan to dropbox. Very hassle-free once you have it set up and great at adjusting for angles and lighting

Dropbox
I have enough storage that I can access almost any non-video, non-system file from my computer, whether the computer is on or off. Has an offline viewing feature for almost any file

Procollage
Lets you stitch pictures together, which I find useful when I need to scan certain documents like passport or insurance cards or something like that

Video D/L
Lets you download any video (shows a Save icon once the video is playing) then can share it to any app that stores/plays video

Infuse and VLC
Use together for watching video. Infuse is very polished and has cover art, cast, episode/movie descriptions. VLC will play all formats including MKV which cost extra in Infuse. VLC also allows audio playback in the background which is nice if you have a video you need to hear but not see

Imgur.com
Not the app but the website which is good for uploading photos online and getting a direct link without a bunch of barriers like with Photobucket. It's a little slow and sometimes the upload fails but it's otherwise useful

Musictube
Listen to youtube videos in the background while you browse Safari or do whatever

 

Mine is made by Devstar Apps. I got the pro version for free (not sure if it still is) so I hope the free one still has good features included