Sorry if this question has been played to death, but what are the most popular textbooks that I should be buying/reading in order to get the most out of skritter as a beginner. Assume I have no knowledge of Chinese.

The Integrated Chinese series is very good, most colleges with a decent Chinese program use it and I see lots of people on the internet using it if they're doing their own self study routine.

http://www.amazon.com/Integrated-Chinese-Simplified-Characters-Textbook/dp/0887276385/ref=sr_1_1?ie=UTF8&qid=1339864580&sr=8-1&keywords=integrated+chinese

New Practical Chinese Reader
http://www.skritter.com/vocab/list?list=list12

try these, online and free:
pdf 1000 word textbook http://edu.ocac.gov.tw/interact/ebook/1000_words/into.htm (top left)
1000 word interactive site (same material)
http://media.huayuworld.org/interact/ebook/1000_w2/index_classList_0.html

pdf for 500 word textbook http://edu.ocac.gov.tw/interact/ebook/digitalPublish/MContent.asp?Lang=E
(ignore the one 'with sound' as it doesn't work, just bigger download)
500 word interactive site (again same as 500 word pdf book)
http://media.huayuworld.org/interact/ebook/digitalPublish2/cn500/class/shock/index.htm

If you don't have a textbook yet, you should start with the Skritter Chinese 101 list while you look for one: http://www.skritter.com/vocab/list?list=agtzfndyaXRlLXdheXIWCxINVm9jYWJMaXN0SW5mbxjfn_lNDA