I shoot mostly people, sometimes sports and cars.. I'm thinking of buying a 300Ws (battery powered) strobe to carry with me and probably one or two modifiers for situations where speedlights just don't cut it (they will still be used for rim etc.). I was planning to get an octabox and a beautydish, the strobe comes with the standard reflector.
I know it's a very difficult question but what would you say is the "best" or most useful size for an octabox? I obviously want something much larger than the 60x60cm (24") softboxes i'm now using with speedlights but it still needs to be easily portable and not too cumbersome to deal with when shooting alone. My options are 120, 150 or even 180cm (47", 60", 70") - I'm leaning towards the 150 which I think should give me even light for full body portraits but is still OK to deal with.
Thanks for your suggestions..