My g/f initially struggled with precision pathfinding and timing related events, especially when involving an analog stick. Ocarina of Time fixed all of that though.
She fell for the style, gameplay, and plot and couldn't put it down. She replayed it years later in a quest for a no death save record.
Your a better gamer after OoT, I can't recommend it enough. (Especially for girls.)
Hmmm, interesting, I've got a GameCube somewhere, but also got a Wii on the way, so I may pick up OoT just for me, never mind her!
I really enjoyed XCOM, FFVII, Eets, the Myst games (although that's going back really far, they are still my favorite), Fable series, Portal, and many co-op games. I probably would have never played Borderlands on my own, but playing co-op with my significant other was fun. We're currently playing Monaco together.
I've had trouble finding many JRPG games that I can really get into, outside of the Final Fantasy series.
Edit: Oh yes Mass Effect! Great series
Just had a quick Google of Eets, I'll definitely add that to the list!
I'd stay clear of Spelunky in that case. It's a roguelike which requires a lot of trial and error. Very frustrating to most hardcore gamers never mind trying to introduce someone to them
Limbo is very time focused too for making jumps. No where near as bad as Spelunky and still accessible but just a heads up.
Double Fine make some great games too; The Cave (similar to Trine), Costume Quest (light hearted RPG) and Stacking (puzzle-adventure).
Mass Effect and Dragon Age series will keep her busy on the RPG front for a while. Although older, Star Wars KOTOR 1 and 2 are great (and you said she is a sci-fi geek).
The Witcher 1 and 2 are some of the best PC RPGs in recent years.
Surprised nobody mentioned Portal 1 and 2 yet. They have twitchy-jump timing puzzles but a lot of females love the series.
Plants vs Zombies, Peggle, Braid, could go on and on
Although not available on Steam/Origin I still think Minecraft deserves a shout. She'll love it if she is on the creative side.
Thanks for the heads up on Spelunky. I've played a little bit of Limbo and I think she could just manage it.
I'll definitely check out The Cave & Costume Quest, but I've already picked up Stacking, I cannot wait to give that a go!
I completely forgot about SW KOTOR! I love both of those games and they're exactly what she'd be into (even though she hasn't seen Star Wars?). If I recall correctly, she could probably get into ME1 as it's very similar combat to KOTOR, but ME2 / 3 went more third-person shooter focused, didn't they?
Dragon's Age would also be perfect, another I completely forgot.
Unsure about The Witcher, I've only played a little bit of the first one, but I think it might be a bit too testing for her timing / reaction skills. I vaguely remember a lot of swordplay and timing involved.
Portal games would be good, I had been thinking about those.
Plants vs Zombies is a great shout, I'll add that to the list. Was the sequel any good? I'll check out Peggle, and Braid is towards the top of my list - I adore that game.
She loves Minecraft, so as long she doesn't expect me to play (I'm awful at stuff like that), that can go on the list!
Let's face it one of the most popular game with girls remains WoW.
Nah, she absolutely hates WoW.