I guess the first real band I ever got "into" was Pink Floyd, mainly via exposure from my oldest brother John. Brian, the middle (me being the youngest), exposed me to Elton John and more "piano"-based rock as he was into the piano, played pretty well too. I then latched onto mainly Pink Floyd and that style of music. I went more into the ambient rock, the oldest got into Nirvana, while Brian still latched onto Elton John and Billy Joel. To this day I remember having fights over whose rock was better, especially around the time of 1990-1994 ...
Once I moved onto college I definitely entered a Pink Floyd phase, I ended up at one point having over 200 Pink Floyd CDs, a lot were RoIO and bootlegs ... I was exposed then to Grateful Dead, Phish, and more "college" rock but ended up latching onto The Orb, Autechtre, Radiohead, Blur, Oasis type rock. By the time I graduated I still pride myself on being one of the first US Gorillaz fans ... I remember playing "Client Eastwood" for friends and them telling me I was crazy thinking it would be a big hit in the US, this was March, but June the album dropped over here and well, you know who they are now.
I went through some major fluctuations during grad school and from the period of about 2001-2004 when I listended to just about anything, from country, to rap and hip-hop, to classic rock. I always go back to the bands that to this day I still listen to that I listened too over 10 years ago they being:
Morrissey and The Smiths
Those being the "grandfathers" while I also have been fans of:
Super Furry Animals
The Beta Band
Boards of Canada
Manic Street Preachers