[quote name='Rozz']The nano one is better for portability, it looks great, and will last you longer because it uses flash memory vs a hard drive, which is why it doesent have a larger storage (4 GB is still large for flash). If you plan on using it for a long time I'd get the Nano, but if you only want to use it here and there I'd get the 30 GB.[/QUOTE]
Truly, the flash drive (nano/shuffle) versus hard drive (video ipod) can't be overstated. I'd recommend the nano if you plan on working out a lot, although I just upgraded to a 60GB Video from a 20GB 2nd gen ipod, and never had problems with either (the video's only a week old, so don't take my word for that there).
I have around 500+ cds on my 60GB ipod right now, and I have 30GB still available. I will never ever ever have to swap songs out or do anything like that, and I don't have to use my PC or external HDD to store my songs. That's nice. I'm not the kinda person who makes/changes playlists, so having a large ipod is nice versus a nano.