As a teenager in the late-nineties I went up to Denmark Street with a grand intention of playing a Rickenbacker through a valve amp. Confronted by the frostiness of late-nineties Denmark Street hospitality, I lacked the balls to go through with my plan and ended up doing a quick circuit of the shop and pointing to the first set of strings I saw behind the counter before leaving with a mixed sense of shame and relief. A tale as old as time.
Of course the strings in question were Fender Original Bass 7150s and this started a lasting romance. It helped that for a young bassist, the smoothness of the nickel, compared to the scouring nature of the steel roundwounds that was all my local shop would carry (Rotos in the orange packet). This made playing so much easier. I loved the initial zing, gradually developing into a mellow thump and less obnoxious than the clang of steel roundwound. Santa got me a set of 7250s once and that ruined the dream of Christmas for me.
Over the years I have put flats and steel roundwounds on various basses, even those weird black nylon things, but the bass I have always picked up the most and gigged the most has carried Fender pure nickels because it has the best compromise between steel roundwound and flatwound. The only downside is that the sweet-spot does not last long and I am too lazy to change them as often as I should.
Also they changed from a gold sil wrap to no wrapping at some point. I muched prefered the silk wrapped version, both aesethically and tonally.