You always need more space than you think you will. When I bought my iPad less than a year ago I doubled up on what I thought would be more than enough, and already I'm feeling cramped.

Never worry out technology outdating you, unless it's a question of not being able to get the bits and pieces.   Cassettes and vinyl and VHS tapes all still work fine. Maybe storing the records and the tapes can get tricky over the years, but that's not a problem that's going to arise with an iPod.

I can never understand how you get people who lament that they can't access their old home tapes because they got rid of their VHS players. Fools.