Source for the best maps of Israel in English is Carta.
A good map like Carta's Touring or the spiral bound Road atlas is indispensable for driving around Israel.
I see people every day finding their way around with this very detailed Old City of Jerusalem Map. This one is for greater Jerusalem and also has an Old City map.
If you need a map of the roads as well as trails, mountains, rivers and streams of Israel Carta's Physical Map gets recommended.
You'll be happy to know that you can find Israel on Google Maps now. Lots of Hebrew, but you can get directions in English.
And here is the link to download Israel maps for GPS.
Have a wonderful trip!