Even though skitter is THE core of my study aids i like to combine it with some other resources to get the most out of my study time. It is all about context, context and context.  Here are some resources that I have found  to be very helpful in conjunction with skritter. Lets start with the lovely skritter bookmarklet 
http://www.skritter.com/vocab 
Very convenient way to add new words to your study list. Since I need to look up the meaning of new words before I add them I use the Zhongwen plugin to Chrome.
 https://chrome.google.com/extensions/detail/kkmlkkjojmombglmlpbpapmhcaljjkde 
Now I need some texts to read and that i can get here for example:  
 http://www.tom61.com/ 
It is a Chinese site for children but it do have a lot of stories, songs, films, games,education etc. A fun way of learning Chinese if you use the other mentioned tools. Other sources for shorter Chinese texts is e.g. this one: 
http://www.uiowa.edu/~chnsrdng/Chinese_reading/Intermediate/intermediate.html 
texts sorted by level. Or this one:
 http://www.pthxx.com/01ld/index.htm 
You can't study without some Chinese music and the biggest site for that is 
 http://mp3.baidu.com/ 
We need some fun as well so Chinese comics made by an western/Chinese family might be  something 
 http://www.mandmx.com/2008/09/07/ping-pong-in-china/
 Or this one that explains  my family situation 
http://www.mandmx.com/2008/08/31/east-west-cooperation/ 
And yes, for all listening I am a big fan of 
 http://chinesepod.com 
I take most of my words from their lists. They also have a very large database with example usage so for words i study in skritter i usually look them up in Chinesepod to get the word in many different contexts. I have also started to use their example sentences in skritter since they are usually very good.
For references we always have the natural ones:
 http://zhongwen.com/ 
 http://www.yellowbridge.com/chinese/character-dictionary.php 
 
 http://www.nciku.com/ 
Those are some of my current favorites, please add yours.
    

