Don't know if this warrants its own topic, but sometimes I'm too busy paying attention to the battlefield and completely miss chat messages due to them being in the same place as kill messages. (Despite them being in a different color and everything)
I think either the kill messages should be separated from the chat somehow, or chat messages should make a little "click" sound when received. This shouldn't apply to the voice commands.
I also think it would be useful if the chat log preserved text colors.