Seems to me like the 58 doesn't really need a pop filter, the built in windscreen works pretty well for most. Now is the time when you start gear lust...
Microphones?
PreAmps?
Outboard Compression?
You've got phantom power if you get the ub1202, so you could get a condensor for vocals. I'm kinda liking the Beta 58 mic for a good ole dynamic that you could use live too; A/B one at your local music store sometime. Way less mud than a regular 58 if you really want "quality vocals".
Then if you get a good mic, you'll want a good preamp. Then if you can pick up all the wonderous definition from a better mic, how about some compression? (my next purchase). And then... and then... and then...
Will it ever end (my Visa card wonders the same thing)...