iPhoto should be for storing photos. It can take videos too but I wouldn't do that.
iTunes is probably the best place to store your videos. It's made for holding all forms of media (except photos).
I suggest downloading a tagging program like MetaZ or similar and tagging your videos so that they have names, dates, descriptions, etc (just like iTunes music or podcasts). Tag them as "movies" or "tv shows" or "home movies". Personally, I tag mine at "TV shows" so that the "Season" field can be set to the year in which the video was shot. This keeps videos with names like "Christmas", "Easter" etc neatly arranged by year rather than having to hunt through 10 videos named "Christmas" to find the one you're seeking.
If you have or get an

TV, this will come with the bonus of very easy access to any of your videos on your television.
iMovie can store video clips too but it is more about editing video into a final form. Conceptually, you import your raw videos there, edit them, then render out the polished-perfection, final version. Tag that and drop it into iTunes. Play it on your computers, iDevices, or

TV.
Video is a storage hog. Consider storing your videos on a big external drive. You can click an option in iTunes to NOT import media into your iTunes library. This means it just points to wherever the movie is stored (which would be on that external drive). It won't look any different in iTunes but the big difference is that it won't eat up your internal storage if you go this way.
Lastly, I'm guessing these are home movies you've shot yourself. If so, some/all of them will become increasingly precious with the passage of time. Be sure to work out a solid backup plan so that a bricked hard drive doesn't wipe out those memories. That happens much too often because people skip this part of things. Don't do it. It's much cheaper to buy a backup hard drive now than to pay data retrieval services to try to recover your home movies later. Just do it.
Think offsite backup if at all possible so that a fire/flood/theft doesn't wipe them out either. One good (low cost) strategy there is to gift your home movies to other family members who might want to watch them too. Grandparents, Aunts & Uncles, etc. A good old safe deposit box can be a great option too.