I upgraded to 7.10 Gusty quite late (December 2007) and also installed a fresh version on a new box (AMD XP64 3200).

As usual, I document here the major system tweaks:

• For Firefox
  1. ScribeFire 1.4.2
  2. make link 3.0.2
  3. All-in-One Sidebar 0.7.3
  4. Show Anchors 1.51
  5. Custom Buttons² IOT use URL-Tools 0.4
  6. Web Developer 1.1.4
  7. User Agent Switcher 0.6.10
  8. All-In-One Search 1.67
  9. How’d I Get Here 0.1.2
  10. Delicious Bookmarks 1.5.44
  11. ShortShip Pro 2.0
  12. Web Developer 1.1.4
  13. Sage 1.3.10
  14. Some new (& useful) Search Engine Plugins / Search Providers
  15. (maybe, not tried) TargetKiller 0.4 IOT solve Downloads not visible in Download Manager
  16. about:config tweaks like those I used to tweak Firefox 2.0.0.3 and Open search results in a new tab

Most Firefox tweaks are now reported in the Wiki