Winamp makes a better loader than Itunes, it gives you much more freedom over your iPod and supports lots of features that Itunes does not like adding album art from a directory instead of embedding in every mp3 file. Get that and the ml_ipod plugin.
On my iPod right now, 5881 songs, 106 videos, and just the three games that come stock. That still leaves twenty one gigabytes free, but a lot of my music I just don't feel the need to carry around. I also keep a couple Disney movies on there as well, for the kids to watch if we're out some place. It's a lot easier to watch stuff on an iPod than a laptop if you're waiting at a restaurant or something.
The notes function from Apple is pretty lame because files have a max 4KB limit, I suspect they didn't want people using it as an ereader too. And of course, Apple likes to control everything so there's no SDK for anybody to make a better one. Otherwise I could program that same Tetris game and give it away for free when they want to charge $5 on the Itunes site for it.
You can use a filesplitter on text files though, breaking them up into 4KB segments. Copy them into the notes directory, and it will read whatever is in there so they don't even need a .txt extension. It's handy some times with game walkthroughs so you're not tethered to reading them off a PC instead. Same with the photos function, you could put game maps on there and the like.