Changing technology

Hi-
I have recently come to realize how much I enjoy good sounding music. It seems on the digital front, the technology evolves rapidly. I recently purchased the 700i from simaudio with transmission audio speakers. I think that I am safe for the next 20 years. The question is the source. I recently ordered the Music Stream 6 from Cambridge Audio. I do not have a cd player, nor turn table.

I have no real music collection except for 20-30 LP's from the 70's. There are great music options on the internet. Bottom line questions:
What are the pros/cons for starting staying with the internet as the source; if I start my own collection of music, what is the stable technology for managing the music.
Thanks!