The best replacement for zonealarm is comodo.

The best alternatives to zonealarm are rated as following:
★★★★★  comodo
★★★  windows firewall
★★★  avg
★★★  norton
★★★  online armor
★★  kaspersky
★★  comodo firewall
★★  avast
★★  windows 7 firewall
★  microsoft security essentials
★  sygate
★  bitdefender
★  windows 8 firewall
  outpost
  norton 360
  kerio
  windows xp firewall
  comodo free firewall
  kaspersky internet security
  xp firewall
  pc cillin
  windows defender
  eset
  sygate firewall

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

Other search terms related to zonealarm and their ratings are:
★★★★★ avast
★★ ics
You have in mind a companion for zonealarm and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of zonealarm in all years. Click on graph for more.
zonealarm
comodo
windows firewall