Like most who have played bass for a while, I've owned many head/cab combos always looking for the perfect tone. Of course, the perfect tone means something different to everybody. The tone you seek is defined by the music you'll be playing.
For me, the absolute perfect tone for the style of music I play is an ampeg all tube head and ampeg 8x10 cab. However, I don't want to lug around more than 250 pounds of amp gear so I needed to make some compromises.
I can reasonably mimic the tone I'm looking for in a form factor that is much easier to deal with. I play a GK 1001-RBII (very light - like 18 pounds) and an SVT 610HLF. If I could play a light little cabinet to generate the ridiculous volumes needed in my too loud of a rock band, I would. However, some laws of physics can't be broken - or something like that.
I first plug in through a BBE Opto Stomp to a SansAmp PBDDI (this box is the whole trick to tone manipulation). This set up allows for everything from crystal clear tone all the way to down right distorted tone. It's very versatile. In my opinion, these SansAmps are as necessary as your bass.
You say you're looking for "good tone and no fuzzy sounds" and you need a tone for "slap bass and funk/rock and maybe some metal". There are many roads to get to where you want to go, but I can only tell you the road I took.
I don't think you can go wrong with the GK RB1001RB-II. Your volume needs should probably dictate your cab choice. If you need to be stupid loud then you need more speakers (generally speaking). Whatever you decide, I would HIGHLY recommend you also get a SansAmp Bass Driver. This, all by itself, will allow you to shape your tone from slap style to a SVT grind with a twist of a knob.
Good luck in your search for the perfect tone.