Simple addon that stores (by default) 500 of the last messages received.
You can edit core.lua and on the top change this number, even add or remove events so certain messages do not get logged, like channels or achievements in guild chat...
Overall easy to use (no configuration in-game) and works perfectly fine. Next time you go a dungeon and re-log, disconnect, reload interface, log on an alt for some enchant that someone whispered you about earlier -you will know what deal was about without having to ask them to repeat themselves!
Should work for anyone, no mater what chat addon you use or if you run the game without any addons at all.