it might be a tad pricey still, but i have the sony ericsson k750i (and i got it from myworldphone.com. ive bought about 4-5 phones from them, theyre great). and everytime i forget to charge my ipod the previous night, i use my phone to play music for my morning jog. it comes w/ headphones too so you wouldnt have to worry about getting them w/ the phone. it also has expandalbe memory so if your gf later wants to put more music in, she can.
also, when a call does come in, i think the music does cut off.
its pretty much a complete package except that it doesnt have 850, which isnt THAT much of a problem for me cause im in chicago.