I've never actually played a "Big work" of Liszt, and I'm not planning to until 5 years from now

, but from listening, here are some of my favorite "moderately big-very big" works:
-Hungarian Rhapsody no. 11 (One of my teachers told me this is a good starting Hungarian Rhapsody. Looking at the scores, I think there are some easier ones, but I think they sound like crap. #11 is one of my favorites as a listener.)
-Concert Waltz on Themes from Lucia and Parisina (A long time ago, Thalbergmad said that this was a less demanding work than many other opera transcriptions. For now, Ill trust him. From the point of view of the listener, I LOVE it. It sounds so familiar! Thalbergmad seemed to like it too.)
- Erlkonig & Ave Maria ( OMG I LOVE TO LISTEN TO THOSE PIECES

Some other pretty Schubert-Liszt song transcriptions for me are Die Forelle, Die Stadt, Serenade, Doppleganger, Barcarolle, Die Junge Nonne, and Gretchen. There is also a group called "Soirees de Vienne" that Liszt wrote. They are paraphrases on Schubert Waltzes. It can be tedioius to listen to them all, so if you don't hacve the sheet music at hand to make your own decisions, then I'd suggest these: nos. 6 and 9.)
-6 Polnische Lieder (A transcription of songs by Chopin. Honestly, I don't know how long it takes to play all these, but I'm pretty sure it's under 15 minutes.)
-Widmung (It's a great transcription. I think it can bring up many beauties that the Schumann original just doesn't have,)
-Funerailles (I don't know why I'm suggesting this, but I love the slow part and the heroic part.)
-Tarantella (IMNSHO, this is one of Liszt's not-to-demanding "virtuoso" works. It doesn't have really that many "riffs", for me the main technical difficulties are repeated notes (not really too bad) and a few akward arppegios. I think it's really interesting, lively, impressive, yet beautiful & exquisite all packed in the same piece.)
Seriously though, I have no idea the difficulties of these pieces; I just found their approximate difficulties by looking at people's lists and recommendations (I. e. donjuan's rankings; Thalbergmad's recommendations, etc.)