I had PS2 at launch and loved Tekken, SSX and ISS, I thought I'd be a PlayStation person forever.
I hated the Xbox when it came out but that all changed when I played Outrun 2 in a Gamestation and thought "Christ, these graphics are amazing". On a whim, my dad bought one for me and suggested Xbox Live.
Xbox Live back in the day with Halo 2, PGR2, Mechassault, Rainbow Six: Black Arrow, Splinter Cell, Ghost Recon... some of the most fun I've ever had.
I love the PS2 but I had way more fun on the Xbox and I loved the S controller too.
Plus the ability to rip music to the HDD was killer, custom soundtracks in-game was amazing for a teenager.