I have had a couple, and now have a pentax optioS 5i, and its the business.
Check one out on-line for a full run dopwn of the spec, but its the smallest I've seen for the performance. Complete with protective case, its the same size as a packet of fags.
I`d go along with that,I`ve got the casio version ZX55,5megapix,400 pictures on one charge,hour of video with sound(pending on card)one second start up and 1/100 of a second shutter delay and if you haggle at jessops you can get em for £170
I like the casio exilim range fantastic battery life, good size and transfers info from SD card and a huge screen to view the pics you have already taken
I just got me a Praktica DCZ 4.4 . 4 mp with video for less than £70. Normally have Olympus but me old one packed up - then had another but that didn't last long so bought this the other week whilst in Scotland.
Can say I'm happy with it so far. Easy to use, small and good photos with large screen.
Have printed out some really good A4's with it with no compromise on quality as far as my non photographic eyes can tell.
I have a Sony DSC-P200. Although I havn't had it for long,so far I'm very pleased with it ( and it has a Carl Zeiss lens).Prices vary a lot,so certainly worth shopping about
I've got a Kodak 3.2 Meg pixel jobbie that has done well. I have seen that Sainsbury have a deal on with the 4Meg pixel version plus "printer dock" which is a recharger etc, print straight from the camera and/or download to PC all for £149.99. Bargain I reckon.
I've had a few cameras and other things to consider beyond the obvious megapixel and size issues are;
speed of startup and write time - very frustrating if you are ready to capture a "kodak moment" but the camera isn't.
what you are going to use it for. If it is just casual use or small pictures then 2Mp or 3.2Mp should be fine - and one CF or SD card should last you a whole holiday.
size of battery charger. If you are taking it on holiday then you will need to take the charger with you (or have a couple of spare batts).
It may be that one of the newer cameraphones (now up to 2 Mp) may do you fine if its just for casual shots.
This is just from the perspective of a point and click guy so different things may take priority if you are not.