I loved MvC too, but was a bit surprised none of my friends thought it was quite as awesome as I did. We had spent MONTHS playing SoulCalibur, so I guess I could understand their POV. Almost every other game (fighter or otherwise) paled in comparison to SC. Once MvC2 came out, I was stunned and amazed. It's simply a top-tier game with so many characters to pick from, great gameplay and it looks gorgeous. I still absolutely love it, and the DC is my go-to version.
So SoulCalibur and MvC2 are at the top of my list, but Dead or Alive 2 is also up there. Does Ready 2 Rumble Boxing count? Of course there are the great Neo ports of Mark of the Wolves and Last Blade 2. Street Fighter III was fun. I also have a soft spot for Psychic Force 2012. It wasn't even that great but I remember liking it quite a bit, so that oddball would probably be on my list too. I haven't played it in years though, and it likely didn't age well.