itunes memory sizing

What do you mean "normal size"? If that is how many songs you have, that is how many songs you have. If you want them to take up less HDD space, reencode them to AAC or something.

 

Newsflash: 120/3 = 40

 

That is 7,000 songs encode at the lowest possible quality settings. Depending on your encoding settings 40GB seems fairly reasonable for 5,000 songs.

Here is a link to several tutorials on the Apple website that can answer some of your basic questions...
http://www.apple.com/itunes/tutorials/#import

 

There is no such think of "normal size" for a song. Your songs seem to be slightly less than 7 Megabyte on average. How large a song is depends on how long it is, and what compression you used. Most manufacturers calculate the number of songs by assuming 4 Megabyte per song, that is about right for 4 minute songs at 128 KBit/second. If you use 256 KBit/second, your music files will be twice the size. If you use lossless compression, they will be a lot bigger. You may have a few songs using lossless compression or even uncompressed, or just a lot of songs at high bitrates.

But don't worry if one third of your iPod is filled. Are you going to buy another 10,000 songs really soon? If not, it is no problem.

About "reencoding": The best choice is to leave everything as it is, because your iPod doesn't mind being one third full, or half full, or 99% full. But if you want to, there are two ways how you can reduce the size of songs:

1. You can put all your CDs into your computer once more, using better compression. When you use iTunes, AAC is the best compression method, so if you imported all your CDs as MP3 192 KBit/sec, for example, you will get about the same quality using one third less space if you import them as AAC 128 KBit/sec, because AAC is better than MP3. Or if you imported lots of music as AAC 256 KBit/sec, and you decide that your ears can't hear the difference between that and AAC 128 KBit/sec, you can import everything again at higher compression.

2. You can tell iTunes to convert your music to more compressed and smaller format. This is usually not recommended because every time the music is compressed, you lose some quality. So if you imported a CD at 256 KBit/sec, you can tell iTunes to convert it to 128 KBit/sec, but you get better quality if you import the original CD again, at 128 KBit/sec.

 

Convert them using a program such as Handbrake. It's straightforward and offers a iPod preset for both 5G and touch iPods.