You haven't mentioned what version of iMovie you will be using, so:
iMovie 11 - cameras supported:
iMovie 9 - cameras supported:
iMovie 8 Camcorders supported:
Digital camera RAW formats supported by OS X Lion:
Digital camera RAW formats supported by OS X Snow Leopard:
aside Klaus' list, which lists 'Apple-tested' cams only, any AVCHD-cam will work with iM, except in 3D-mode or in Dolby5.1 mode.
you will not find any actual device anymore with internal harddrive - this was a 'interim technology', now obsolete.
focus on your needs:
• external mic-plug needed (doing interviews)?
• wide-angel needed (indoor)?
• super-zoom needed (sports/nature)?
• low-light performance (again indoor)?
• manual controls ('cinematography')?
• interchangable lenses ('cinematography')?
• frame-rates beyond video-standards (60(120/240fps for slowmo)?
• size, weight, ext. battery loader (usage)?
camcorderinfo.com gives excellent overview and in-depth info ......
my actual personal favorites are Panasonic 707 (biggest bang for price) and Panasonic x800 (legacy) x909 (awesome 3ccd technology but pricey).
my actual device is not a camcorder but a 'bridge', a LumixFZ38.
but I probably have diff. needs and a smaller wallet than you