Quickoffice
For $7.99, QuickOffice is definitely worth it.

It's worth the money just to be able to save .doc, .xls, and .txt files from GMail to the SD card, which it does. I have a few e-mails in my inbox with attachments, which I kept in hopes of saving to the SD card someday. Now I can do just that!

Pros:
  • Can save .doc, .xls, and .txt to SD card, which could not be done before.
  • Can view .doc, .xls, and .txt files. 
  • Can edit file names.
Cons:
  • Can't choose which folder to save to when downloading attachments.
  • Can't download right to card, rather you have to "view" file first, then save. (not that big of a deal)
  • Doesn't support .docx or .xlsx. (yet, hopefully this will change soon)
  • Biggest con: Can't edit the files. (again, hopefully this will change soon with updates)
It appears from the description on their site that Office 2007 support, PowerPoint, and file editing are coming at some point.


Features and stuff (from Quickoffice website):
Access
Access your Word (.doc) and Excel (.xls) files from memory card or from GMail attachments.
View
Simple to use features provide a rich user viewing experience only available with Quickoffice.
Word and Excel Common Features
  • Open .doc and .xls files from memory card or from Gmail attachments
  • Easily Zoom in or out
  • Smooth scrolling throughout the application.
  • Orientation automatically adjusted based on the sensor
Word Viewer Features
  • Text wrapped doc display eliminates left-right scrolls
  • Displays all formatting, bulleted and numbered lists, tables and images
  • Follows telephone numbers, hyperlinks, and email addresses
  • Fast first page view to quickly identify document
Excel Viewer Features
  • Spreadsheets display in familiar Excel UI
  • Resize column and row
  • Display cell content with cell and number formatting
Manage
Manage your files from memory card with our easy to use file manager.
  • Navigate folders
  • Rename, delete and view file properties
  • Sort file listings by file name, type, size and date modified