Plenty of manga readers out there, many of them free too. It's pretty easy getting files on them with iTunes, but Dropbox is very handy for getting them on there. DL via the Dropbox app, and then open them up in your app of choice. Stanza is pretty handy as it also does pdfs and other ebook filetypes. Comic Zeal is the slickest comics app so far but not free.
iBooks is out for Asia as of right now, so i've been buying all books from Kindle (and stealing the stuff i already have on paper, mostly, where i can get a decent copy of it). Kindle also works on iPhone of course so it's really handy for reading a chapter or two on a short train ride etc. I can burn through books at a crazy rate now.
For RSS stuff, News Rack is really great.
For video stuff, Air Video is quite possibly all you need.
For news, check out the npr app, NYT, WSJ, BBC News - all excellent. And of course anything you can browse in Safari, like Google News, is all there.
If you need more than Dropbox for file transfer/sharing, Air Sharing HD is pretty useful. It has ftp and network drive access, so you can get at all your files at home (or uhh, anyone else's, if they happen to be running a FTP...). Pricey though.
That should get you started!