Okay people. I am going to tell you how I fixed it for me. If you are using mods like I am (i.e. minimap).

I currently use Magic Launcher who's details and download are below:

Features

• Minecraft

  - selectable minecraft.jar

  - automatic version detection

  - configurable window size, also maximized

  - selectable minecraft folder

  - selectable java executable

  - java memory limit

  - java custom parameters

  - show error log

  - remember user

  - configuration profiles

• Mods

  - load mods dynamically without changing minecraft.jar

  - META-INF does not have to be deleted

  - automatic mod compatibility checking

  - external mods detection and compatibility checking

  - shortcut to external mods folder

  - configurable external mods

  - automatic mod requirements checking (ModLoader, ModLoaderMP, Forge, GuiAPI)

• Design

  - Minecraft style

• News

  - Minecraft

  - Reddit

  - Twitter

  - Blogspot ...

• Coming soon

  - Minecraft update

Download here: For Windows and For Mac

The reason I post this, is you can still load modloader, and the minimap mod without effecting minecraft.jar.

The next part you DO need to affect your minecraft.jar.

First step is download the class file attached called mq.class.

Next step is to open up minecraft.jar (a fresh unmodded one) and delete META-INF

Next copy and past or import the mq.class into minecraft.jar and replace the old one.

Open up magic loader, and add in your addons, then click okay and then login. Connect to server then your white text is now colored again. You can also do this without any mods or anything else added at all.

I haven't been able to get this to work with optifine so gimme some time to figure it out.

To do this without magic launcher, then simply open up the minecraft.jar and replace the old mq.class with the new one...

Let me know if you have any other questions...

Edit: I had to make it in a zip file due to the forum not liking class files. So just unzip and then follow directions...

Files: 

mq.zip