Using different *types* of strings makes a HUGE difference to the tone of your bass. No, really!!
Roundwound strings - very bright, "zingy" sound, especially when new (first, say, 10 hours or so of playing - they settle down a bit after this). Stainless steel roundwounds are brighter than nickels, generally, but they are both much brighter in tone than...
Flatwound strings - much rounder, less cutting tone than roundwounds (even older ones), with a smoother feel to play and less fret noise.
Most new basses come with roundwounds and I guess the majority of bassists prefer these most of the time (I do, but I enjoy playing flats on occasions - I keep them on one of my basses all the time so that I've got this option available).
Differences between brands are generally less important than the difference between these two types. You can get compromise strings like halfround or groundwounds that are supposed to feel a bit smoother without losing too much of the roundwound brightness. They are a lot closer in sound to rounds than to flats, but a little smoother in feel.
Hope this helps.
EDIT By the way, filling out your profile on here helps people to know a bit more about you and maybe offer better advice.
Why on earth did you pick "Herpes" as a username?
Always a good idea when you get a "new" bass.
You can't be serious? 
