Nick Kranz: It's the Giants, and it's not really very close. I nominally root for the 49ers and the Warriors, but I can't pretend that my fandom for those two teams comes anywhere near my fandom for Cal and the Giants. The Warriors were so bad for so long during my formative childhood years that they completely failed to make any meaningful impact. I'm just a fringe bandwagon fan now, more happy for long suffering friends than I am personally invested.
As for the Warriors, basketball is my favorite sport. As a kid, I loved Kobe and Shaq (because kids are bandwagoners by nature), but I always thought as a kid that you were supposed to stay loyal to the team you're closest to. And through a whole load of terrible seasons (and one great 'We Believe' year), the Warriors have become an excellent team that is probably the most fun to watch in the NBA. After seeing Klay Thompson tear through a Cal defense for 36 points in Haas my freshman year, it's great to see him exceeding the potential he exuded at that point. It's a far cry from Bimbo Coles, Danny Fortson, and the ashes of John Starks.
In October of 1989 I was almost 9 years old and at the peak of my A's fandom. Rickey Henderson had joined the team that summer and immediately became my favorite player and sparked the A's to the World Series. I'm not sure why, but I hated the Giants more than anything in the world and so for the series I convinced Old Bear 71 and my mom to let me plaster the house with pro-A's/anti-Giants signs. Old Bear71 tells me that one of the signs said that Will Clark was mud, as that was about the worst insult my 8 year-old self could think up. I like to think my signs put the A's over the top that year.
I still root for the A's and will attempt to raise my sons to do the same. It's a little tougher now that I live so far away but I still watch the early innings of a lot of A's games on MLBtv and always wear A's stuff once the season rolls around. And I still hate the Giants.
As a Cal fan, it's been more rewarding to root for the A's in recent years because Bob Melvin is a Cal alum. And this season they're regularly starting Cal alumni Marcus Semien and Mark Canha. Even during down years (like this one) A's games are always a ton of fun to watch live or in person.