DC1 to be perfectly honest was a great stopgap between RE2 and 3. Coming out in July 99 helped ease the long summer drought and now that I look back, the game's structure is classic RE (I'm gonna steal Yama's simile and say it's the PS1's CV). One of the best looking fully realtime PS1 games too. DC2 is something I still adore for different reasons. It's also RE4's precursor.

As you know I'm a big fan of Onimusha, particularly 2. I still haven't finished the 4th and never got around getting the JPN version as I sold the US one unwisely a while back. That was Ono's first real big budget game as a producer and I still think the difficulty broke the US version. It's irritating and the fact that my favorite action game is Itagaki's NG and its various versions says a lot (beaten on Master Ninja).

I remember being stunned at the fact they changed the puzzles for all 3 versions of Dino Crisis depending on region. I don't know if that's ever been done to any other game.

How about Onimusha vs. RE in terms of villains?

Guildenstern vs. Birkin/Alexia?
Nobunaga vs. Wesker?