I own two, only two signature basses I've ever really had;
Yamaha RBXJM2; It was the second bass I bought. Bought from the local store, I wanted a 6 string because I used to play on my brothers TRB and I loved it. My other bass was also a Yamaha so it was natural for me to go with another Yamaha and the JM2 was by far the best in the RBX at the time and half the price compared to the TRBs. Still have and is probably the bass I've played the most throughout the years even though it sees little use these days. Fantastic instrument though, it still plays fairly decent and the truss rod has never been adjusted and I've had it for 14 years now.
Ibanez K5; Who haven't had one of these? Affordable, nice instruments with a decent sound, well rounded for metal. I've recorded two albums with it and they've turned out pretty good. It's now my go-to live bass for one of my bands. Sadly it sits in the rehearsal space in the other end of Norway so I never get to play it regularily. I made a speedramp for it and refinished the back of the neck to make it even smoother. I've never been an avid fan of Korn though, but I like Life is Peachy..