Simple, but this should allow you to tweak your settings a bit easier.
Make sure you have "/console shadowlod 0" set for the 1st 3 macros.
HIGH:
/console overridefarclip 1
/console farclip 1600
/console horizonfarclip 6226
/console groundeffectdensity 256
/console groundeffectdist 140
/console smallcull 0
/console skycloudlod 3
/console characterAmbient
/console extshadowquality 4
/console environmentDetail 2
MED:
/console overridefarclip 1
/console farclip 1400
/console horizonfarclip 2112
/console groundeffectdensity 128
/console groundeffectdist 140
/console smallcull 0
/console skycloudlod 2
/console characterAmbient
/console extshadowquality 3
/console environmentDetail 1.5
LOW:
/console overridefarclip 0
/console farclip 1277
/console horizonfarclip 2112
/console groundeffectdensity 96
/console groundeffectdist 140
/console smallcull 0
/console skycloudlod 1
/console characterAmbient
/console extshadowquality 2
/console environmentDetail 1
NOTE - Make sure you type "/console shadowlod 1" for the following settings.
DEFAULT: - Default for WoTLK
/console overridefarclip 0
/console farclip 1277
/console horizonfarclip 2112
/console groundeffectdensity 64
/console groundeffectdist 70
/console smallcull 0
/console skycloudlod 0
/console characterAmbient 0
/console extshadowquality 0
/console environmentDetail 1
LOWEST: - Equiv to Classic WoW / TBC
/console overridefarclip 0
/console farclip 777
/console horizonfarclip 2112
/console groundeffectdensity 32
/console groundeffectdist 35
/console smallcull 0
/console skycloudlod 0
/console characterAmbient 0
/console extshadowquality 0
/console environmentDetail 0.5
Additional Tweaks:
-ENGINE-
m2Faster - Adds additional threads used in rendering models on screen (0 no additon threads, 1 - 3 adds additional threads)
Note: If you have a Duel Core or Quad Core System (Multi Processor too) this will show an increase in performance in situations with lots of models and players/npcs on screen.
-SHADERS-
ffx - Global Shader Control (0 disables all on screen effects, 1 enables them)
ffxRectangle - Renders effects on a rectangle based polygon (0 for Off, 1 for On)
ffxGlow - Bloom/Screen Glow and Underwater Wave effect (0 for Off, 1 for On)
ffxDeath - Death World Screen Glow, Greyish Blue (0 for Off, 1 for On)
ffxNetherworld - Mage Invis Spell Effect (0 for Off, 1 for On)
ffxSpecial - Borean Tundra or DK Starter Area Eye Haze (0 for Off, 1 for On)
fixedfunction - This forces the pixel shares in the game to run on the 1.1 path. (1 for FF Shaders, 0 for Programable Shaders)
For some older machines they will receive a decent speed boost.
hwPCF - Enables a more efficient method for rendering extShadow effects. (0 for Off, 1 for On)
Example usage is:
/console ffxNetherworld 0
Side Note - What does CharacterAmbient do?
Let Dr. Death Knight explain,
/console CharacterAmbient
0 = Default basic ambient lighting on characters.
0.1 - 1.0 controls how bright this ambient lighting is.
1.0 is equiv to when you click a character and they fully highlight.
No Value disables all character model ambient lighting so when they do light up from an external light source it looks far better and not washed out.
No Value tweak was disabled in 8905 and 0 up works now. :/
-Fog Changes in 8905-
It seems like certain zones have a fog limit.
Where it'll draw the fog from this point on no matter what the setting is for Farclip, but will continue to draw terrain behind the fog to the point I have set.
http://forums.worldofwarcraft.com/thread.html?topicId=9679888244&sid=2000
EDIT:
Corrected a typo on shadowlod.
Also added advanced settings.
Added Fog explanation
Corrected extShadowQuality typo. >_<
Example Screenshots
extShadowQuality 0:
http://i33.tinypic.com/29frnfc.jpg
extShadowQuality 4:
http://i34.tinypic.com/21cshom.jpg
skycloudLOD 0:
http://i36.tinypic.com/iwkrgp.jpg
skycloudLOD 3:
http://i38.tinypic.com/2uqk4mq.jpg
-Badlands-
farclip 777:
http://i38.tinypic.com/24vv6ro.jpg
farclip 1277:
http://i34.tinypic.com/296d8u8.jpg
farclip 2000:
http://i34.tinypic.com/2a4vkso.jpg
-Terro Forest-
farclip 777:
http://i35.tinypic.com/2vcye7p.jpg
farclip 1277:
http://i38.tinypic.com/axi5us.jpg
farclip 2000:
http://i36.tinypic.com/33d8tn8.jpg
-Searing Gorge & EF-
farclip 2000:
http://i34.tinypic.com/33lhug5.jpg
http://i34.tinypic.com/23s7vhu.jpg
http://i38.tinypic.com/v6ivqd.jpg
environmentDetail 1:
http://i35.tinypic.com/21mbt09.jpg
environmentDetail 2:
http://i33.tinypic.com/sl0a3s.jpg
Not the best shots for environmentDetail. :/
/console smallcull 0
This draws tiny doodads much much further away.
Default is 0.4, 0 disables culling.
May also work in Classic WoW/TBC.
Small Cull 0.4:
http://i36.tinypic.com/2cyr56o.jpg
Small Cull 0:
http://i34.tinypic.com/2cf5pwy.jpg
extShadowQuality 0
[LOWEST] Precomputed terrain and blob PC/NPC shadows.
extShadowQuality 1
[LOW] Precomputed terrain and dynamic PC/NPC shadows.
extShadowQuality 2
[MEDIUM] Full environmental and PC/NPC shadows, low-res, med-dist.
extShadowQuality 3
[MED-HIGH] Full environmental and PC/NPC shadows, low-res, lg-dist.
extShadowQuality 4
[HIGH] Full environmental and PC/NPC shadows, hi-res, lg-dist.
extShadowQuality 5
[VERY HIGH] Full environmental and PC/NPC shadows, hi-res, lg-dist, dynamic shadows to the horizon.
extShadowQuality 6
[ULTRA] Full environmental and PC/NPC shadows, hi-res, lg-dist, translucent shadows, soft shadows.