Welcome to iMovie Discussions fatcat,
Do you want high definition or not? HD requires large hard drives, consuming upwards of 70 GB per hour. On the other hand, standard definition uses 13 GB per hour, very easy to manage on a laptop computer.
Besides the hard drive issue, HD also requires more equipment and software, if you want to put HD movies on a DVD.
You can get very nice results from a SD camcorder and if you buy a miniDV tape (SD format) or HDV tape (HD format) cam, you can also use iMovie HD6, which offers a better editing platform to make the type of movies you have mentioned.
Research all types of cams here:
http://www.camcorderinfo.com/
Happy New Year!