Just got back from a 3 night break in Beirut and I am already wishing I could go back! We absolutely fell in love with the city and will definitely return again. We stayed at Golden Tulip Serenada Hotel in Hamra which was very good (see my review). We ate at Abdel Wahab in Achrafiye on one night and Karamna Restaurant in Nejmeh Square (Place d'Etoile) the next night and both were amazing. We had 4 different mezes, a mixed grill, lots of arak, nargile and dessert at Abdel Wahab and paid 107000 LL (just over $70) and at Karamna we had pretty much the same amount of food and arak (we had a warm appetizer instead of the dessert) and we paid 121000 LL (around $80). Both meals were brilliant and we would have happily paid much more than this! We also had lunch and drinks at Al Mandoloun Cafe in Achrafiye which was very nice ($45 including tips).
We had pre-booked a taxi with Trust Taxi to pick us up from the airport. They are an ok company but they are not reliable in terms of answering emails. They reply straight away if you ask for a quote but when it comes to booking, it is almost impossible to get a confirmation from them. I started emailing them almost a week before our arrival to book our transfer which I wanted to book as a return transfer and I managed to get a confirmation of our pick up from the airport just a few hours before our arrival (even then they thought it was going to be the next day!). They didn't confirm our transfer back to the airport so everyday in Beirut I had to email them which they never replied to. We had an early morning flight so we had to leave the hotel at 4:30am, they finally emailed me back after I got back home to say they would pick us up from our hotel at 4:30pm that day :) They charge 20000LL if you just call for a taxi when you get to the airport but if you want to pre-book and have them meet you at arrivals, they charge $20. They say this is because of parking at airport but we noticed the driver only paid 2000 LL for parking.. Nevertheless, it was good to have him waiting for us as we arrived late at night and wanted to get to our hotel quickly. When Trust taxi failed to take our booking for the transfer back to the airport, we just asked the taxi driver taking us back to the hotel on our last night to come and pick us up to take us to the airport and we agreed on 20000 LL for this transfer. As for taxis within the city, we never paid any more than 10000LL for a taxi ride. Make sure you ask them how much they charge before you get in, from our experience, we found that most of them say $10 first, and if you say "I'll give 10000LL", they just say "OK" :) Some have asked us how much we would like to pay and we said 10000LL and they agreed. I don't know if we could have got a cheaper rate if we haggled but we thought this was a fair price so we were happy to pay it. Following the advice of some previous posts here, we always paid the driver at the start of the journey which worked well. We asked the taxis waiting outside our hotels for a rate once and they said $15 for a short ride which we declined. We found that walking out to the main road in Hamra and hailing a taxi there worked out cheaper.
We walked a lot both during the day and at night and we always felt very safe, in fact safer than we do in most cities. Some streets are badly lit at night which may not be ideal especially if you are on your own and in some parts of the city walking may not be very comfortable due to heavy traffic or pavements not being very wide but in general, I would definitely recommend walking to explore the town. Make sure you have a good map with you or even better, have a navigation application on your mobile!