Wait for a little while. It's almost certain that Sony is going to release a slim version of the PS3 within the next few months (possibly at a reduced price) and the old version will most likely be discounted or bundled to remove excess inventory.
A decent article with all the rumors about the PS3 Slim. I've also seen reports from a Gamestop employee that they've gotten in big $299 and $349 stickers, the kind they put on consoles.
Just tell her the best thing to do right now is wait. That's what I'm doing.
If she has an HDTV and has the PS3 properly set up (with HDMI) then Blu Ray is going to be higher quality then DVD. Right now the PS3 has no manufacturing issues like the 360.