python

  has basically become my weapon of choice lately. here are a few

python

  libraries that i've found useful and a few i haven't used but look useful.

urllib2
urlib2 is a

python

  module for fetching urls. supports simple GETs and POSTing to forms. a nice howto: http://www.voidspace.org.uk/

python

 /articles/urllib2.shtml

mechanize
easy to fill and submit forms without using

regex

 . maintains client state with cookies automatically. kinda like using a browser. based on the

perl

  module of the same name.
http://wwwsearch.sourceforge

.net

 /mechanize/

Universal Feed Parser
haven't used this one yet but probably will soon. parses feed like the name says. i like that it doesn't involve DOM traversal.
http://feedparser.org/

PyRSS2Gen
for creating rss programatically. again, no DOMs. haven't tried it yet either.
http://www.dalkescientific.com/

Python

 /PyRSS2Gen.html

Beautiful Soup
parses html/xml. useful for scraping because it handles broken html.
http://www.crummy.com/software/BeautifulSoup/

pycurl
for the curl people
http://pycurl.sourceforge

.net

 /

thanx for adding those

Don't forget PIL (

python

  imaging library) , MysqlDb, and the threading module (i know its default but you mentioned urllib2 )