That's another cool thread.
Like David Bash, I can probably trace my ephiphanies in distinct phases as
well.

The first came c.1983-1984, when I discovered there was more on college
radio than the trad jazz shows my mother listened to on Saturday mornings.

The Wesleyan University station in Connecticut, WESU-FM, seemed to be the
repository of everything that was cool about college radio at the time, and
I vividly recall staying up late and listening to it via the crappy
transistor radio I kept secreted under my pillow. When I got my first,
honest-to-god stereo later in 1983, I started listening to WESU on there.

From college radio, it was an easy step to IRS' Cutting Edge TV show on MTV,
and thence to the record bins to track down the bands I was being exposed
to. That continued, more or less unabated, the entire time I was in high
school.

All those early moments were revelations -- discovering Husker Du, the
Replacements, REM, the Athens bands, and punk at the same time. It was
dizzying.

The second, distinct phase came after college when, through my girlfriend at
the time (a student at Northwestern University) started exposing me to the
new crop of indie bands. I have to confess that my tastes had calcified
somewhat, so it was nice to be shaken out of my complacency, and have my
eyes opened to an entirely new universe of music.
At roughly the same time, I began subscribing to emerging Internet mailing
lists, including one dedicated to The Church which, in turn, introduced me
to a whole universe of Australian bands.

The third came within the last three to four years through subscriptions to
other lists, including Paisley Pop and Audities. In tandem with that, I
started playing music seriously again, which exposed me to still more stuff,
and began reviewing and writing for music mags.

John.