Why you need a vinyl collection and not just mp3's
Here's a good article that explains the difference between digital (mp3's & CD's) vs. records.
http://electronics.howstuffworks.com/question487.htm
For a while I always rolled my eyes when my older musician friends talked about the audio quality regression of this current generation but my records do sound much richer.
You won't be able to hear all the tone nuances by listening to just those mp3's or CD's you have. It becomes important when listening to instruments such as drums or harmonica. There's also something romantic and nostalgic about playing records. To me at least.
Luckily, I live in a city (Seattle) that has an abundance of used records stores. If you don't, check out amazon, ebay, and discogs.
-Taylor