One goal in music that I appreciate is the creation of interesting, layered, complex, challenging pop.
One of the important things to remember about this sort of stuff is that you need to have something immediately fairly catchy and understandable, but you need to layer things in that reward repeated listens, and don't end up being boring..
Off the top of my head, Shiina Ringo, Bumblefoot (on his latest CD), and Jethro Tull are among the most successful at this sort of thing.
Bumblefoot - Real
Bumblefoot - Normal
Shiina Ringo - Identity
Shiina Ringo - Shuukyo
Tokyo Jihen (Shiina Ringo) - OSCA
Jethro Tull - Velvet Green
Jethro Tull - Quizz Kidd/Crazed Institution
Judas Priest - Deliverin' The Goods
searching for clips, I found this cool video of Bumblefoot covering Judas Priest's Running Wild