I'm a 60 yr old grandma, with cataracts. I love my BRIGHT YELLOW Samsung Rugby A837. I find it easy to locate anywhere I leave it, including in my purse. It's water and drop resistant (made for the Army) and has large raised keys for dialing and texting. It has a camera and video as well as a SPEAKER PHONE. It's internet capable, GPS capable, music capable, has multiple labeled preset alarms that she'd only have to turn "on", and various tones to let her know whether it's a phone call, text, alarm, etc.
The drawback for this phone is that the back light remains on 10 secs. max, but you need only press an additional button to turn the back light on again to see how long you've been talking, on hold, or if the person disconnected.
I'm very happy with mine!
Assuming AT&T, what would be the best cell phone for grandma? No web, no apps, no gps, no mp3 (although FM radio might be nice). SMS capable (at least receive, she won't send) and a camera would be nice. The Just5 seems like it might be the best bet, but I'm not sure if there might be something better out there these days (my google research kept coming back to the JitterBug, but I'm not sure that's the best either).