I don't know about stylescripts, but this is what I do. (this assuming you have Firefox)
Install Adblock plus. Subscribe to the USA list. This blocks almost everything you could ever want blocked anywhere. (there are other lists for other countries)
Then, for neopets I add in these filters:
http://images.neopets.com/adslug_728.gifhttp://images.neopets.com/728ads/http://images.neopets.com/sponsors/#div(ad_wrapper_fixed)
#div(ad_wrapper)
Plus this exception rule:
@@http://images.neopets.com/items/*
(because some neopet items have ad_ in their name)
Bingo! Absolutely no ads on neopets.