Help Needed to Plan trip to Israel: Amount of time needed and best sites?

"Best places" in Israel or anywhere else is entirely subjective. One person's must see is another's must avoid.

Would you be travelling by public transport or renting a car?

And end of this April or next year? Meaning you have one week or almost a year to plan this? April isn't guaranteed warm enough for the beach except in Eilat.

Yes, all the above, plus:

It is possible the onward ticket thing is required if arriving by air. I know it is not required when arriving overland.

With that kind of time I suggest you plan on spending two days at Petra and one day / night in Wadi Rum. They can be reached from Eilat by crossing the border to Jordan and taking a taxi from there.

Good luck.

Onward ticket ? How are you planning to get back home ? I assume that you will have return tickets from somewhere that you can show if anybody asks, which I doubt. It is quite common for tourists to fly into Tel-Aviv, cross overland to Jordan and return home from Amman (many British tourists do this on EasyJet).

How much time to spend in Israel ? I suggest a minimum of 10 days if you want to see all parts of the country. Your itinerary should be:
- 1-2 days Tel-Aviv
- rent car and drive to Caesarea, Haifa , Akko, Galilee and Golan - 3-4 days
- Dead Sea - 1-2 days
- Jerusalem (return car) - 3-4 days
You do not need a car in Tel-Aviv and Jerusalem because of the traffic and parking problems.
For "historical and religious sites, ... natural beauty, hiking" - look at the National Parks website for ideas:
http://www.parks.org.il/BuildaGate5/general2/company_search_tree.php?mc=378~All
Note their "Money-saving ticket" offer.

While 10-14 days is a enough time to see the highlights: Jerusalem, Dead Sea, Masada, Tel Aviv, Haifa, Acco and the Sea of Galilee, but if you have more time and are interested in nature and history, then you have endless possibilities.
This is a great source for nature and hiking info:
http://www.tiuli.com/default.asp?lng=eng
A few I'd recommend-
A walk through green forests to a Crusader fort:
http://www.tiuli.com/track_info.asp?lng=eng&track_id=8
Through the forest to an ancient Synagogue
http://www.tiuli.com/track_info.asp?lng=eng&track_id=4
Canyoning in the Golan
http://www.tiuli.com/track_info.asp?lng=eng&track_id=124
A world class bird watching site:
http://www.agamon-hula.co.il/?lang=en_US
An epic Crusader battleground:
http://www.tiuli.com/track_info.asp?lng=eng&track_id=17
Ancient rebel hideout:
http://www.tiuli.com/track_info.asp?lng=eng&track_id=7
Nabatian Ruins:
http://www.tiuli.com/track_info.asp?lng=eng&track_id=81
http://www.tiuli.com/track_info.asp?lng=eng&track_id=47
Geological marvel:
http://www.tiuli.com/track_info.asp?lng=eng&track_id=53
Desert oasis:
http://www.parks.org.il/BuildaGate5/general2/data_card.php?Cat=~25~~989817747

No need to worry about the onward ticket, Israeli officials will not prevent you from entering Israel if you don't have one as long as you can explain how and when you plan to leave the country.

For Petra, I would strongly, very strongly advise you to plan two full days to discover the site. The bare minimum would be one full day. It's gigantic and one of the most beautiful things on earth. Combining Petra with a night in the Wadi Rum, as suggested above, is a good idea.

In Israel there are tons of things to see so it's a matter of taste and everyone will have different ideas for you. On my side, I would say:

• Visit Jerusalem's Old City, including the Haram Al Sharif / Temple Mount, the underground tunnel at the Western Wall, the view from the rooftop terrace at the Austrian Hospice (if you can book a room there)
• Visit the Crusader city of Akko (Saint Jean d'Acre) on the sea, sleep in a hotel inside the Walls and have dinner at seafood restaurant Uri Buri on the port, which I consider to be Israel's best restaurant (Akko's Old City is populated by Palestinians citizens of Israel, with Uri Buri being the only Israeli restaurant there, famous for its creative chef).
• Visit the Kabbalist city of Safed in Galilee, have lunch at Rafa's restaurant inside the Artist colony at Rosh Pina village, see the view at the Mount of Beatitudes over the Tiberiade Lake
• Visit Tel Aviv (Neve Tzedek village, and the bars around Rotshchild and Lilenblum), visit Jaffa (the Palestinian old neighborhood with a flea market and gorgeous seaviews)
• Stop at the Dead Sea (can also be done on the Jordanian side, which personnally I consider to be more beautiful)

On the Palestinian side you can visit Bethleem of course, but also Hebron's Old City (take a Palestinian taxi in East Jerusalem to drive you there, it's easier than the bus). Ramallah has a fascinating nightlife if you like to go out. One of of the most beautiful hikes you can do in the Middle-East is the famous Wadi Qelt hike near Jericho, which stops at Saint Georges Monastery, but if you travel during summer it will be extremely hot and should be done with a guide.

• Visit Bethleem and Hebron's Old City

I would fully agree with the above lists of highlights (Jerusalem, Tel Aviv, Sea of Galilee, Dead Sea, Haifa, Akko etc). I'd add also Tzfat and Nazareth if you have time in the north. If you're going to go down to Eilat to cross into Jordan for Petra, then you should also make a stop at the Ramon Crater (Machtesh Ramon) at Mitzpe Ramon. The crater itself is spectacular and it is truly a getting-to-one-with-nature kind of place!

Worth noting that Safed which I mentionned is the same city as Tzfat which VTP mentionned. There are at least four of five different ways of writing this city's name, which is definitely worth the trip.

Actually CatW. There are 4-5 ways to write Tzfat in its transliterated form. There only one way to write it in Hebrew.

As for the Old City, there is also a Jewish and Armenain Quarter. You can find gorgeous ceramics is the Armenian Quarter.

The Israel Museum and Rockefeller Museums in Jerusalem are well worth a visit. Wonder through the market of Machane Yehuda, in west Jerusalem. it's also an good place for lunch

Thereis a few very good Humas places in the Old City-Humas Lena and Abu Shukris

Thank you everyone for your responses. All of the information is extremely helpful. We are actually flying into Israel very shortly, so we have only about a week to plan this trip. We are planning to spend about a week with a friend in Tel Aviv, and then spend about three to four weeks traveling around Israel. While we are in Tel Aviv, we are going to try to figure out our route and how much time to spend in the different parts of Israel. It sounds like some parts of the country are best to see by rental car, but which places are best by public transport? We would like to take public transport as much as possible. Also, besides Petra, is Amman worthwhile visiting in Jordan? And thanks to your responses, we are now planning to spend two to three days in Petra to really see this area...