i wouldnt recommend the .25-06 as a first rifle (i have two of them now, but looking back i am sure glad i didnt get one as a first rifle - i had a .223 and shot thousands of rounds of white box winchester ammo through it at $5 a box). ammo is expensive and hard to find, and when you do find it your selection is usually limited to choosing between the 90gr or 120gr Winchester Super-X hollowpoints.
IMO the .25-06 is something you get
after you have 2-3 other guns and you know what you want. that said there are some good deals on .25-06's at LeBarons right now in their clearance section.
get her something that has the option of readily available, affordable plinking ammo so she can get a lot of practice in. the best thing you can do is buy her 5-6+ boxes of ammo, take her out to the range and have her shoot, shoot, shoot until she is comfortable with the gun. many guys just hand their wives or g/f's one of their softer shooting guns and think thats it -- but you can tell that the women are still nowhere near comfortable with the gun, or are even intimidated by it.
its going to take more than just asking in a forum what she should get - you have to visit gun stores and make sure the gun fits her and that
she likes it. i cant stress this enough - theres so much psychology to getting the average woman to feel comfortable with a gun (if you have the non-average tomboy type who will just pick up any gun and say
'lets git'r'dun' then great). most women i know will either love or hate a gun on sight - so if you want to buy her a stainless/synthetic T3 and she goes to the gun store and falls in love with a blued/laminate Ruger (and it
fits her or can be made to fit her) - dont talk her out of it and get her the T3 anyway. her liking the gun is going to go a long way towards her feeling comfortable with it.
if it needs it, have it fitted with a good aftermarket pad, and then you start taking her out to the range to get her accustomed to
her gun.
check out the Ruger Compacts and Frontiers -- most women i know that typically cringe at the sight of your typical remchester instantly like them and think theyre 'cute'

i think the laminate helps too - chicks dig the laminate
more food for thought: .308 and 7mm-08 both have managed recoil loads widely available for them that have less recoil than a .243.
but seriously, take her to the gun store and have her actually help pick out something she likes and that fits her, dont just choose what sounds good in a forum. your gun dealer might have some suggestions as well.