Many guitarists who are just starting out may not be sure about what strings to put on their guitar, and of course that all really depends on your particular style of playing. One thing to keep in mind is that the thinner your strings are the more tone quality diminishes.
My recommendations: Light gauge strings for electric and steel string acoustic guitars if your playing style includes any type of string bending, otherwise you could choose thicker strings if you so desired.
When it comes to classical guitar hard tension gauge nylon strings are better than normal tension gauge nylon strings in my opinion based on my own experience as a guitarist.
Due to the nature of the bass and the role that a bass player plays in a band or jam situation string bending is not really a concern even though one could do string bending on a bass guitar if they so chose to. With that said, Light to medium gauge bass strings are recommended, but some players may choose to use thicker strings.
When it comes to buying electric, bass or steel string acoustic guitar strings, I usually opt for Dean Markley, GHS or D’Addario, and for classical guitar, I opt for La Bella or D’Addario.