I like bottom-end, so the best choice will be the 1x15, but i've heard that a 1x15 doesn't sound good by itself. It needs to be paired with a 2x10. In the other hand, with another 2x10, I can have a consistent rig for small and big gigs, but I won't get the low-end I want.
I'm talking out of my ass? I'm new to bass rig, so any help is appreciated.
As far as bottom end and driver size, it depends on the driver and design of the cabinet.
Regarding a 1x15 sounding good by itself, again depends on driver and cabinet design. A single cab with 1x15 can sound great. I've been using my Electo-Voice 1x15 for gigs on and off for near 20 years now.
I know the tech stuff, along with a million opinions can be a bit overwhelming. There are some basic "rules of thumb" you will learn as you gain experience, but I've seen the rules broken so many times with great results. So don't sweat that too much.
Most importantly, go play a bunch of 1x15 cabs. If you find a good sounding stand alone 1x15 that you like, chances are pretty good it will do well paired with another cab.
Remember. In the beginning, the most important ears to please are you own.