I asked myself the same question not long ago. At the end I decided to buy a single-speaker combo because it was simply easier to carry around and had more than enough power and volume to be played (only) at home. I tried out a few different amps with 2,3 and 4 speakers - and seriously considered at least one of them (Victoria 35310) - and now I regret not buying it because it had more clarity, more balance and a brighter/fuller sound.
If you are into combos, I would at least have a look at them and try a few out (Fender Bassman for instance). I found most of them far too heavy and way too loud for playing at home, but this might be different for you. They are generally also a lot more expensive.
As for a head and separate cab, I haven't really looked at that, but going down that road opens up a enormous amount of options - mixing heads and cabs, different speakers, etc.