I use mine in a similar way and I have found that Clawsmail is great for handling email and adding/receiving attachments. Abiword is great for documents and supports the .doc format. Use Gnumeric for excel stuff.

All of these things can be done within the standard OS, if you find that it isn't enough then I would move on to Open Office in Debian.

Why the iGo Keyboard? Is the slide out one just too small? I have fingers like sausages but I am getting pretty fast on it. Most of my document work is reading rather than writing.