A few years ago I made my first real step into the head-fi world, picking up a pair of Shure 420's for use on the road and in loud places. While I've always been a big room speaker kind of guy, I loved the sense of intimacy and the clarity offered by a good set of IEM's, and while my Shures are not quite top of the line, I definitely felt as if I had gotten my money's worth.
In the intervening time, my phones have taken a beating, and without a replaceable caple I fear that my Shures will soon require replacement. When I came back to Head-Fi, however, I was surprised to see the massive uptick in both ultra-high-end and relatively in expensive custom IEM's, the prevalence of user-replaceable cables and available upgrade cables, and the near-ubiquity of portable amps across an increasingly wide price range.
So as I look at the possibility of an upgrade or replacement for my ailing Shures, I am wondering what the new "upper-mid-fi" standard really is. Do inexpensive custom IEM's sound better than top-of-the-line universals? Do portable amps really offer a noticeable improvement for either custom or universal IEM's?
I guess my question ultimately boils down to this: Given ~$500, where would you put your money? On custom IEM's? On top-of-the-line universals? Portable amp? Cables?
For reference, I listen primarily to jazz/funk and classic rock. I love the clarity and fluid mids of my Shure IEMs but I value comfort nearly as much as sound quality.