I am looking at getting Louise a Macbook pro 15". I have just been to a Mac outlet and the guy there tried to advise me to buy the i5 rather than the i7. I explained to him that Mr Louise uses a 5D MK2 and would " occasionally " edit photos and HD video footage on the Mac. He still said that all I would require would be the i5 and that I would be better off with the 17", which I would prefer Louise had, but I was looking at getting her the 15" as it was available with the i7. Is the bigger screen more important for
her our

needs or the smaller screen with the i7 processing.
Advice from Mac users gratefully received.
Stew
I have a 15" with the i5, 4GB RAM and I Hi-Res Anti Glare screen. I don't see any reason for the i7 because I have no issues editing in Final Cut Express and Photoshop CS3 with my current set up, however if you have the money to spend, it never hurts to have more power and/or more RAM. I personally would not want the 17" because that extra size is a pain in the ass to travel with. You should really consider packing and portability before getting the 17".
My other suggestion is unless you are in love with a glossy screen that the Hi-Res Anti Glare is a great upgrade and well worth the money.
So to summarize, if she is just going to edit using iPhoto and iMovie I would save your money and go with an i5 15" with hi-res screen. If she is going to use Final Cut Pro, Aperture and Photoshop extensively she might want to go with the 15" i7 but I don't think she will really need it.