iTunes can transfer videos in MP4 format from PC to iPad using Movies app.
Remote control of a PC is suggested to be done by free TeamViewer app.
The second article notes Powerpoint show on the iPad with Slideshow Remote app.
Photo editing can be done with free PhotoShop Express app.
For transferring files, free Dropbox is suggested (I like using alternate EverNote).
For text, spreadsheet or presentation editing, iWork is suggested using Apple’s formats at $9.99 for each app. There is nothing for editing Office documents.
Editing PDF files can be done with Goodreader $4.99 (I’m using the alternate PDF Expert $9.99).