A success story, to show there is hope, my friends.
i was/am in this situation when i moved in with my gf. We needed a car for us/her to use daily, so my camaro wasnt it. I fought the "used vs new" argument with her, and more specifically, the "buy something outright for peanuts, spend a lil to get it up to snuff, versus making payments on anything contemporary" argument. It came to "well, if you want that, then you pay for it and its maintenance" which was when she wanted an A4, jetta, newish bmw, etc...I dont know that i woulda been able to stick to that, but lord knows i made sure i sounded like i meant business haha.
So we were looking at old volvo 240s and the like. We wound up getting a $1000 peugeot 505 - i checked it out thoroughly, got into the forums for it, and got her to agree (it had AC, power windows, etc, even heated seats, so at the very least, it fulfilled those kind of requirements). That was over 2 years and 40k miles ago.. In that time, she's seen friends buy brand new cars, and at first there was that bit of jealousy. "Well, so and so got one, and they havent had any problems!" Then time passed. Friend's new cars go back to dealers, random electrical problems, CELs going on and off, etc. But our peugeot soldiered on, just with oil changes and brake pads and tires at one point. It took patience and time, but from the examples set by those around her, she came to see the value of a solid old car (its an '84 - i dont consider that "old" but im using her word heh). Now that im bored of the slow ass peugeot (i do like the car a lot, but man, i'd kill for a turbo or a v6 505, or just anything different for a change of pace), she's veto'd selling it every time. "I LOVE PUGGY! YOU CANT SELL HER!"
now i realize a $1000 french car is an extreme example - but i think if you can show, over time, the value of something solid, like an infiniti g20, volvo 240, or loaded and timing-belt-serviced-on-time civic, you might just win this one argument with your loved one. Also, i have considered, in times of extreme duress, just letting her pick whatever color used jetta she wants, and then waiting for when i can say "told ya so!" - but that sorta thing doesnt sound like the makings of a healthy relationship hehe
and i love hearing how friends will take her for rides in their brand new cars, and she tells them the seats dont even come close to the peugeot's =) (most comfortable seats EVAR.)