Home telephone

We have an old corded telephone with caller id mounted on one of the walls. I was wondering if there was something I could get that would let you set different tones depending on who was ringing (like on mobiles). I checked the Argos website and all the corded ones are pretty rubbish.

Then I saw something called Digital phones there and hurray some of them are wall mountable and have incoming ring personalisation!! But I see a lot of them require NIMH batteries. Does this mean they need to be plugged in at some time ?(where we have the phone there is no socket nearby). I know nothing about this DECT thing...could someone recommend a good one at a good price please and maybe explain things? I think we're stuck in the dark ages with the corded phone at the moment so any help greatly appreciated! Thanks

Actually I think probably all the DECT/Digital phones need to be plugged in so it looks like I'll be sticking with the corded piece of crap.