I would suggest the Canon or the HP for the memory card as there is a bounty of SD memory cards out there in 1-2GB capacities so you can shoot pictures of gazelles until
they get tired. The Sony has the bigger 2.5" screen. The canon and the HP have smaller 2" screens. I use the viewfinder just because it sucks the life out of my batteries. The HP does have the best optical zoom 4x of the bunch which would be a bonus as opposed to the digital zoom which is just image interpolation. The Sony has a Carl Zeiss lens but I cannot verify current quality is of the same standard it used to be.
There are models with 3" screens which may be of interest.
http://www.usa.canon.com/consumer/controller?act=ModelDetailAct&fcategoryid=145&modelid=12956