As a resident old $art, I like a lot of different musical styles.
From Tony Bennet to Radiohead. I tend to love Surf (Beachboys) Roadhouse Blues (ZZ and SRV and Bugs Henderson) and even Johnny Mathis (Mr. Silver Throat) since they all need and use bass guitars for holding the music together even if they don't actually play them themselves.
If I were to pick the Ten-Best or Most-Necessary songs for a bassist to learn ASAP - it'd be like this -----------
1) Louie, Louie - but make it your own version 
2) Girl - by The Beatles
3) Samba Pa Ti - The Santana version
4) ANYTHING - by Gino Minelli,
5) China Grove - by The Doobies
6) Something - by The Beatles
7) Show 'n Tell - by Al Wilson
8) Poison - by All The Pretty Horses (they're weird - no, make that: "different" but have a good bass player!)
9) In A Week Or Two - by Diamond Rio
10) Misty - by Johnny Mathis
I think learning songs that you can at least hum the bass-line to are the best - and that's why I picked on The Beatles for at least two songs. They are quite recognizable to almost everyone.
The others are basically for a broad example of what a bass player should be CAPABLE of when seeking work as a pro or semi-pro.
Flexibility is key to finding work and if you at least have some idea of a few jazz and blues boxes, you can get into a groove and "learn as you go" in what you can then channel down to the type of music you want to play for $$$.
You may notice that I didn't include any pop-slap bass and/or speed metal. It's not MY style and this was asked as an opinion and so this is MY opinion.
