The best replacement for sleep mode is hibernate.

The best alternatives to sleep mode are rated as following:
★★★★★  hibernate
★★★  shutdown
★★  hibernate mode
★★  shut down
★  turning off computer
★  power off
★  standby
★  turn off
★  shutting down
★  hibernation
★  turn off computer
★  shutdown mac
★  hibernation mode
★  s3 sleep mode
  turning off
  screensaver
  turning kindle off

Your alternative for sleep mode is not listed? Suggest!
Speaking about sleep mode, one probably shouldn't forget about windows 7 problem.

Other search terms related to sleep mode and their ratings are:
★★★★★ windows 7 problem
You have in mind a companion for sleep mode and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of sleep mode in all years. Click on graph for more.
sleep mode
hibernate
shutdown