I love my Lumix TZ7 - although unfortunately it costs more than £100. The cheapest I see at the moment seems to be £169 at amazon (it should be over £200). I wanted to be able to shoot video too which is why I had to get a more expensive one.
I got it last year and had intended to get a Canon of some kind as I have loved the previous canons I have had - but saw this and thought it even better. But I would have been happy with either.
Whatever you go for though - apart from the advice from Mc about optical zoom and 8-10 megapixels - I would always make sure I have a lithium ion battery in it rather than AA rechargeable ones. I used to have a nikon which used those and they were forever running out after hardly any time at all. in the end I had to keep buying normal AA batteries as a back up and it cost a fortune!
Now I have two litium ones and have one charging while I use the other - although one charge generally lasts me all day unless I am using it to view pictures or take video a lot. (oh yes - that was the other thing - I like the video options on the Lumix and the Canon). The pictures are fantastic.
Milly
PS There is a cheaper alternative Lumix on the site where I got mine which actually looks quite nice...
http://www.rootschat.com/links/0c1i/ and a Nikon Coolpix which looks within your budget
http://www.rootschat.com/links/0c1j/