The best replacement for wep is wpa.

The best alternatives to wep are rated as following:
★★★★★  wpa
★★★★  wpa2
★★★  wpa-psk
★★★  wap
★★  wpa security
★★  wpa encryption
★  wpa key
★  wpa psk
★  wpa password
★  wpa wpa2
★  psk
★  wpa speed
★  wpa2 speed
★  wpa personal
★  wps
  wpa2 personal
  wep2
  wpa wireless security
  wap security
  wpa2 more secure
  aes
  wpa2-psk
  tkip
  wpa2 security
  wpa/wpa2
  wpa performance
  wpa which is better
  rsn
  wap encryption
  psk2
  wan
  wpa better
  wpa how to tell
  wpa wifi
  wpa wireless
  mac filter
  wpa tkip
  open wep
  eap
  wap more secure
  mac filtering

Your alternative for wep is not listed? Suggest!
Speaking about wep, one probably shouldn't forget about open authentication.

Other search terms related to wep and their ratings are:
★★★★★ open authentication
★★★★★ wps
★★★★ wireless n
wpa_supplicant
You have in mind a companion for wep and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of wep in all years. Click on graph for more.
wep
wpa
wpa2