Yeah!
Strings make a HUGE difference in bass tone. Much more so than guitar.
I use DR Fat Beams on my fretted basses. Pricey, but well worth it for me. The tone is awesome and they feel just right. Perfect tension and texture. The DR's usually last quite long.
Something that I always suggest, if you're playing in a hard rock band, is to try flats. Solo'ed, they sound rather dull and boring. But in a hard rock band mix, flats bring out the fundamental of the note and really fit in incredibly well. With rounds, many of the overtone series get lot in the guitar wash and you don't really hear that much of the "sizzle". Flats put out much more of the fundamental tones and can really thicken up a mix rather than trying to compete for sonic space with the guitars.