To find cameras in this kind of price range try the below link to pricerunner:
I tend to prefer Canon but that is personal choice. A lot of the cameras around that price seem to be 4 megapixels or less. For most home use that should be sufficient.
I would personally go into your local jessops and have a chat with them. Don't buy there and then because you might find a £120 camera in Jessops is £100 on an online retailer via the pricerunner website and in my experience Jessops will almost always match prices (unless they are overseas or something).
The following gives a guideline:
So for example if you go for a 4 megapixel camera you can get 256 shots on a 512MB card at high resolution. (Approximately). Use this is a guide, you can always buy more later.
Hope this helps.