Blizzard promised to supply graphic enhancements with the second add-on "Wrath of the Lich King”. If you don't want to wait until the end of the year you might want to take a look at those tips. With those console commands, which can be entered into the chat window, you can increase the object density and change several other things. Even better: create a macro via /macro and copy the following commands into it:

/console farclip 777
/console horizonfarclip 6226
/console groundeffectdensity 256
/console groundeffectdist 140
/console smallcull 0
/console skycloudlod 3
/console characterambient 0

From now one, or after restarting the game at the latest, you will be greeted by an opulent flora and slightly different lighting. The source of the tips speaks of a noticeably increased range of vision but we can't confirm this. According to our tests any higher values don't have an effect.