- The best single player clients for Q1 and Q2.
- The best multiplayer clients for Q1 and Q2.
- Any "must download" content (maps, mods, etc.) that I should be aware of.
BTW, keep in mind that I'm using Linux, so ideally any mods should have released source code that I can compile with GCC 4.x. Windows DLLs will not work, and chances are neither will old Linux libs. (This stuff just isn't an issue with Q3... I don't know what Id was thinking when it decided to drop the VM support for the D3 engine.

[Edit: s/Q4/D3 engine/
