If you're interested in the blues/rock era and would like to explore where all those guitar gods got their inspiration, you need to check out this blog: http://squeezemylemon.blogspot.com/
The name of the blog comes from that infamous line in the middle of Led Zeppelin's "Lemon Song" on Led Zep II. Zep, like most of their contemporaries, were heavily influenced by the blues. The "Squeeze" blog has a ton of stuff about the bluesmasters and some really cool links to some obscure videos. Check it out.