I am currently in love with the offerings from both Atomic and Blizzard, although Rossi has won some awards this year for skis I have never tried, hopefully someone else will chime in with their experiences. I believe your current waist is a 76 and for your height and weight (speaking from experience as we are the same give or take 5lbs) that is not sufficient for a powder day, at least to really leverage a ski's potential. I would recommend the Blizzard Bushwhacker in 180cm sizing. That is an 88 underfoot and great for someone starting to explore powder but still wants the all mountain feel. You can ski groomers on that ski no problem.
I would reply with your rough skiing ability as that could change people's recommendations on skis and sizing.
As an aggressive skier I prefer the Atomic Blog (185cm) which has 110 underfoot. The wider the ski underfoot the more commitment it takes from the skier to control them on groomers and lighter snow days. I am perfectly happy but if you are looking for a ski that you can go anywhere with I would stick closer to 88-98 underfoot. You should be on a ski in the 180cm range, that would ensure you have no problems floating.
Other great options are Atomic Access - great cheap entry ski that is much more ski than its price tag, Blizzard Bonafide - This ski is on my short list for this year or next, I did get a demo on them this past season.