iPhone vs. iPod

It happened so that I had to upgrade a great deal of my electronics all at the same time -- needed a better phone service, my laptop nearly broke and my iPod's hard drive became too small to handle my file collection. After much going back and fourth I decided that there is simply no way for me not to have both a 160 gb iPod and an iPhone. Here are the reasons:

• Of course, the capacity. I envision having to constantly review the files on the iPhone in order to save space and be able to download something new.
• Battery concerns. iPod batteries last a long time and I suppose they have somewhat improved with years. However, my use of the iPod is very heavy every single day. My old one had to run on red quite often. Now, add to this running a phone service, WiFi and some apps. I do not want to end up without a phone all of a sudden because I listened to my iPod too much!
• With 160 gb I can count on having a very spacious external drive to transfer files. Without that I would have to buy another device anyway. Why not make iPod that extra device? I can enjoy it while carrying to files from place to place.
• Using two devices means that the load will be divided between them. Perhaps, breaking down will not be so likely?