It obviously depends on what sort of style you are looking for, which is normally determined or seriously influenced by your Gender, Age, IQ Level and Background.
Some people prefer a basic Hagadda, without many extras, with only translation, and perhaps a few pictures. Those range from the Artscroll Childrens Haggada to the Boruch Chait/Gadi Pollack Hagodo (children up to six or seven generally prefer Artscroll, Kids eight-120 prefer the Gadi Pollak [which is more advanced]).
There is a “Visions of Greatness” Haggadda with a nice Moshol and Story on every piece, which is very illuminating and makes a great [ENGLISH] read for the Ladies.
For use at the Seder, it is very impractical to have a Hagadda with lots of Pirushim, which require lots of page turning, and there is no time to look things up at the Seder anyway. However, for preparation, there are thousands of excellently produced Haggados for sale! For nice, sweet “vertelach” of varied style and from a range of sources, see ??? ??. For a more heavy (buty excellent if you are leading the Seder), see R’ Shimshon Pincus’s Hagodo. (I think R’ Yackov Galinsky has a Hagodo as well).
Another extremely interesting Haggadah is the “Seder Aruch” – it is a 3 Volume set, and the Third Volume is the Haggadah. It goes into all the Minhagim and Halachos with all the different reasons (Pshat Remes Drush Sod!). Also very important for the one leading the seder.
The Toras Chaim Hagodo is not so easy to use, but another excellent Sefer brought out with a collection of the Rishonim (Rashi, Ritva, Rashba, Shibolei Haleket, Avudraham, and a few more I cannot remember) which are very “yesodosdik” to know, but with less things you would want to say over at the Seder.
I’m afraid I have no idea in the Chassidishe market, (although I had a Rebbi in school who was very into Likutei Kerem Shlomo, but I have no idea)
— BTW — Lots of people are saying that Seder is not for Lomdus/Halacha, it is more for Hashkafa and Emunah — you are 100% correct that a focal part of the Seder is about Emunah understanding and reliving the Geulah. However, discussing the Halachos are also a chelek of the Mitzvah – See SHULCHAN ARUCH where the ???? explains ???? ??? ???? ????? ???? ??????? ????? ????? ????? ???????? ?? ??????? ????. This is HALOCHO.
(If anybody is looking for seforim who discuss the Lomdus involving Pesach, there is a set of Seforim by R’ Moshe Shternbuch called ?????? ???????, and another excellent set of seforim called ????? ???. [There is also a sefer brought out with a collection of all the Brisker Toros, but i don’t remember the name.)