There are so many excellent amplified phones for landlines made these days, but I want to mention one of these phones that I especially like. The Panasonic KX-TGM450S cordless phone has great amplification (50 dB) but I found these other attributes that really make this phone special.
Another option I like for this phone is the fact that once you have entered a name and number in the phonebook, the talking Caller ID will mention the name of the person when they call instead of just the number.
The one frustration I have had is that the phone is a little complicated to program. The instructions offer two ways to program the phone; going into the Menu and looking for what you want to change or looking up the codes to program the phone. While this sounds great in theory, it just makes it seem more complicated. Part of the reason for the codes is because there are so many options on this phone.