I can recommend Panasonic. I have the older version of the link below (without an answering machine) with a couple of extra handsets and haven't had a problem with them at all, they came recommended to me.
The sound quality is excellent, volume of the ringers and speakerphone is excellent, battery life is great and they are kiddieproof !!!!
This is the link to the newer model, currently £49.75 from Argos, you may be able to get it cheaper elsewhere;
I hope this helps.