There are so many on the market! Maybe repost his in the forum Digital Media & Photos?
Anyhow, what I looked for was:
small and light (obviously)
decent viewfinder (NOT LCD screen - you don`t want that
showing on certain attractions!)
manual exposure (don`t use auto exposure outside - any bright lights or sky will ramp down the exposure, giving a sillhouete effect on darker objects - usually buildings! And you want to be able to boost the exposure in darker attractions. Same for fireworks - any bright bursts ramp down the exposure)
manual focus - in dark rides the focuswill get `lost` resulting in a blurred image, and sudden changes in contrast (rides and fireworks) will also throw it. A good tip is lock your focus manually to infinity BEFORE entering an attraction - that way anything inside, no matter how its lit, should be sharp (assuming its more than a few feet away)
Good battery life and availability of extra batteries and fast charger
Lens attatchments - my wide angle converter makes SUCH a difference to fireworks.
Stay clear of digital zooms - they only degrade the quality - look for a good optical zoom instead (10-15x)
If you can, get miniDV format - the quality is much superior to S/VHS/C/Hi8 and you can firewire direct into your PC to edit.
Check where the (stereo) microphone is - some cameras have them pointing backwards, or too close to the lens/transport motors. A socket to plug an external mic in is a bonus.
Finally, again if you can afford it, go for a 3 CCD chip model - again the picture quality is so much better than single chip cameras.
As I said, also post in the media forum - you may get more `tech` replies there!