Liszt was the greatest transcriber of all time. You should check out his opera transcriptions- Norma, the Donjuan fantasy, Grand Concert Fantasy from Sonnambula, Waltz from Faust, Robert the Devil, Rigoletto, etc etc..
He also did a number of transcriptions of Wagner's operas. Personally, my favorite is Liebestod from Tristan and Isolde. It is so touching compared to Wagner's original. The new flavor is very unique and tasteful.
Liszt's 2nd piano concerto has some of the most triumphant moments in musical history, in my opinion. There are times when you just have the urge to flail your arms and stamp your feet to release the euphoric nerve impulses! It's really quite amazing! To me, it speaks as it has that feeling of heading into battle bravely- knowing you are going to die, but going out in a blaze of bravura and virtue.
My favorite orchestral work (other than Berlioz's Symphony Fantastique) is Liszt's Les Preludes. I love the Berlin Symphony orchestra's interpretation of it. It makes you see life in a whole new way. This was the first piece of music I ever heard because my parents put headphones to my mothers abdomen while I was still developing. Perhaps I have been born to fall in love with this work. Unfortunately, I cannot find a piano version by Liszt. The best perhaps is Liszt's student August Stradal's arrangement of it for the piano.
Now, when you say Liebestraume, I know you are refering to No.3 because it is the most popular. It is probably the most likeable of the 3 because it has that timeless melody and builds up to grand finale nicely. Just make sure you check out the other 2 so you arent missing out on anything.
Now, you said you like Liszt pieces that are moving and technically challenging. There are a number of works from his years of pilgrimage that may scratch your itch. The great things about this group is how it represents Liszt in all stages of his life. He worked through them all his life, revising and creating new masterpieces for the world. A common but not too common piece from the 2nd year is Sonetto 104 del petrarca. I have played this work and I must say I have never experienced the piano the same in any other case. It seemed like I was singing rather than playing the piano and the piano acts as my vocal chords. It's an amazing experience and it helps develop your sense of sincerity at the piano. Also look at valley d'Obermann from the 1st year and Les Jeau deau a la villa d'Este from the third year. I cannot think of a piece in existence that represents fountains and the nature of water better than the latter. It also would inspire and influence contemporary and impressionist composers to follow such as Ravel and Debussy.
Liszt has a great number of transcriptions of Schubert. I like his Valse Caprices from Soirees de vienne. Also have a look at Schumann-Liszt: Widmung. Yundi Li plays this piece very well. It is moving and technically challenging as it begins as a simple melody and accompanyment and develops into a robust version of it with flourishing arpeggios and strong marcato.
Liszt's 2 ballades are brilliant and very interesting to compare to Chopin's ballades. Especially Liszt's Ballade No.2- It reminds me of Napoleon for some reason. When I listen to it, I cannot help but imagine swarms of soldiers spreading throughout Europe. It must be the chromaticism of the left hand.
I can go on forever here, talking about my favorite composer! I still havent started to talk about his forgotton waltzes, poetic and religious harmonies, or rare works from his early and late years. (Look at Grand Galop Chromatique) Just go to your local library and get every CD you can find on Liszt. You will quickly learn there is so much more to this fascinating composer than just Hungarian Rhapsody No.2 and Liebestraume No.3.
I hope you found my words helpful.
donjuan