The string life thing, like Dave said, is so personal that I don't think it's something that any one person could quantify into right and wrong. I'm one that doesn't even want to play with new strings until they've sat on the bass for a week. Part of it is I'm really sensitive to tuning and until they settle in, new strings going out of tune drive me insane. I also hate the (to me) harsh zing in new rounds (the thing that Mark hears as the preferable tone of new strings, showing that we all perceive things, even tone, differently). I like to play with new strings for a rehearsal or two before a show so they have time to settle in. I sweat on 'em for a few days and let it all sink in, then they sound right to me.
I have to second Birdie's advice about letting the bass decide. One brand or type may sound great on one bass but crap on the next (or at least not right to your ears). I've fallen in love with the sound of a passive P with flats and think I'll like it even more once I install some that are known to be more full sounding than T/Is. That being said, I pick up a Thunderbird and I want to hear that angry piano. To me it's the same when deciding pick or fingers. The song just sort of tells me as I write or learn the part.