I'm also thinking about putting a quake style console into the game, i've got some prototype code I wrote about a year ago that I might polish off and see about integrating it.
I have my doubts my current project is actually going to turn into anything other than a learning experience (I never really intended to finish it). I might just stick with the roguelike idea with a few quests thrown in though. I'm glad that i'm focusing on making code reusable for future games.
I'm starting to think of some other projects that might be interesting. I had a Super Metroid like game engine written in C a couple of years ago, of which I no longer have the source code. I'm considering starting over with it in C++, but it seems a but unlikely right now.
I've also got the itch to do a civilization type of game. But since it appears that there aren't just tons of them out there i'm a little worried that it might be more work than I realize. Haven't played Civ3, but loved civ, civ2 and Alpha Centauri. I would definately want to handle combat better (by the time I had lost my 5th stealth figher to a chariot unit I was pretty annoyed). Maybe do fighting more along the lines of the old game The Ancient Art of War. Got a few more ideas that i've been writing down, I'll see if enough comes together to ensure the game isn't a complete civ derivative before I get started on it.
But in the meantime i'll still keep working on the current project - shifting it over to OpenGL has been an educational experience, and there's still enough I need to learn about OpenGL that I can use this game as a playground for.