Great conversation. I love talking about anything related to the bass guitar, but get frustrated when conversations like this boil down to who has the most expensive bass. I'm like the direction this thread is going.
When I was "gassing" for the best bass I could afford, I did so because I kept seeing people playing these amazing lines and assumed that the ease and facility of their performance had a lot to do with the instrument and not the player themselves. Then I came across this video by Danny Morris called, "Essential Rock Grooves". The dude would show you the line he had chosen for a performance, then you would see him playing a live performance. For about a 5 minute stretch he played all up and down the neck without once looking at the fretboard. About the last 30 secs, he closed his eyes and played a run from the 5th fret to 19th fret. When I saw that, the two things that stood out for me was"
dude practices ALOT
He REALLY KNOWS his instrument.
Not "I know how to play bass", but I know every single millimeter of my bass and we are one.
That's when I realized that if I wanted play at any level of proficiency, I need to put some serious time in and I need to get a decent bass and stick with it. No more "flavor of the month". No more "trade in and trade up".
Coming back to the OPs topic, the best bass is the one that you connect with on a very personal level, that coaxes you into practicing for "10 more minutes", that provokes you to tighten up your timing so you can lock with the drummer, the bass that makes you take care of it so it will always play at its best.
Its kinda hard to put a brand name on this bass. Someone said earlier to go to every place you can find a bass and play them all until you find the bass meant for you. I went through about 10 basses until I found the one that ended my quest. So I invite the OP to just keep playing different basses until you find the one for you. If you do otherwise, you will only be playing somebody else dream bass.