you might want to take a look at www.camcorderinfo.com
. scroll down abit past the ads on the left to get reviews,101 type stuff and more. great site.
i'd look at the canon elura 100 for what you want to do with it. really popular and well featured with a real 16:9 screen option,mic input,ect for only $350. when you add in extra batteries,firewire cable,tapes,ect you'll be up around $500+ then add a basic waterproof housing/bag and you are up to around $630 or so.
memory stuff you mentioned really doesn't apply as much to video cameras as they use minidv tapes unless you are taking allot of stills with some video cameras. Keep in mind the stills are usually good for emailing and that's about it.
good places to shop are bhphoto.com and newegg.com(newegg has allot of user reviews on the canon too)
bhphoto sells very basic waterproof housings too for cameras for river trips.