Soul Bubbles on DS is simply the best indy game made ever made imho. A true masterpiece of art, gameplay and programming, they deserve an academy award or something like that for it. Jmc.
Very solid game on all fronts, with lots of original concepts. One of the devs actually appeared briefly on the XNA forums and linked to a couple youtube vids of their game engine in progress. It reminded me of Aquaria in the way the engine constructed levels. It's the type of engine I wish was readily available. It allows for so much design freedom.
Rooms: The Main Building How about Rooms: The Main Building? I've never seen another casual game like it. http://www.bigfishgames.com/download-games/3806/rooms-the-main-building/index.html
Tetris is casual and original. Diner Dash is casual and original (original if you miss the comparison with some old handheld such Casio LCD Handheld). Peggle is original (i think it is inspired in Pachinko). Minefield is original ("inspired" in some old ascii games). Pacman is original. i think you can find plenty of original and casual games developed in a pre-internet era. Mule is original (but is not for casual gamers, just i want to mention it ).
I think Fashion Cents was fairly original. When I made it back in 2003, there were very few distinctly female-oriented games. Gender-neutral was the rule, even though the audience for casual games was predominantly female. Now there are lots of dress-up and fashion oriented games, though most of them are time management games and have only minor dress-up style gameplay in them (if at all). There were, of course, dress-up flash games and other dress-up "games", but most aren't what I would call "games" but rather "activities". Ours was the only one I saw that had scoring and objectives and some basic planning and strategy elements to it (to achieve combo bonuses, for example). Also, the game mechanic for Fashion Cents is a bit different. Unlike many matching games, the playing field on this one is not a square board and isn't a match-3. The closest parallel that I've seen is PopCap's Alchemy, in the sense that you put neighboring pieces together based on color or shape, and filling a row clears the row.