The best replacement for adsense is adwords.

The best alternatives to adsense are rated as following:
★★★★★  adwords
★★★★★  doubleclick
★★★★  chitika
★★★  admob
★★★  bidvertiser
★★★  amazon
★★★  adbrite
★★  contentlink
★★  adgridwork
★★  text link ads
★★  miva mc
★★  domain parking
★★  spottt
★★  yahoo apt
★★  affiliate
★★  yahoo
★★  clickbank
★  fullscreen
★  dfp
★  adchoices
★  affiliate marketing
★  amazon affiliate
★  ypn
★  ad exchange
★  nuffnang
  clicksor
  adwords revenue
  adx
  ad choices
  media.net
  google ads
  overture
  project wonderful
  amazon associates
  yahoo publisher
  infolinks
  iad
  yahoo ads
  adword
  tribal fusion
  affiliate programs
  yahoo adsense
  buysellads
  google adwords
  yahoo publisher network
  google adsense
  adchoice
  content match

Your alternative for adsense is not listed? Suggest!
Speaking about adsense, one probably shouldn't forget about wordpress.

Other search terms related to adsense and their ratings are:
★★★★★ wordpress
★★★★ blogger
★★★ tumblr
★★★ site
★★★ other ads
★★ weebly
★★ dfp
★★ blogspot
★★ google sites
★ wordpress blog
★ amazon affiliate
★ blogs
★ chitika
★ blog
★ media.net
★ infolinks
★ youtube partnership
docstoc
bidvertiser
adbrite
You have in mind a companion for adsense and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of adsense in all years. Click on graph for more.
adsense
adwords
doubleclick