Ahh the good old board dilemma .... there is no real definitive answer as it really is "go and try" ... even then you might buy a board that technically ticks the right boxes, you may end up to find it not suiting your style.
What is your riding style .... freestyle, all mountain or freeride (little bit of both) ? It will determine your relative length and sometimes type of board (rocker, camber, etc). With your height/weight a freestyle/park board around 153cm or 154cm is fine (152cm if you really want to go smaller) .... all mountain is probably around 156cm to 159cm.
Onto board technology .... a lot of boards are hybrid camber these days where they have a rocker (or reverse camber as some companies call it) in the middle and then normal camber around the binding area OR vice versa .... this is dependent on the model of the board. A little research into this can go a long way. Some people love the quick turning of rockers while others love the stability camber gives while hooning fast down the slope.
Bataleon boards are different from their competitors as they have a patented design called "Triple Base Tech", this is essentially curved sides that allow easier turning. Now some people love it but others hate it (like Marmite

) as the Bataleon boards can take a bit of getting used to. I've heard some people not liking the Bataleon boards with ice but others claim ice is no problem, again Marmite situation.
Gnu boards have Magna-Traction while are small curves sticking out along the edge that give better edge hold. Some people love it for its ability to hold the edge on all situations but Gnu are a pricey brand.
Currently I have 3 boards, a Forum Pat Moore 155cm (which I'm going to sell), a 154cm Capita DOA (which is still new and it is replacing the Forum board) and a second hand older model 152cm Never Summer Evo which I'm using to practice on kickers/boxes for now. My first board was a second hand Santa Cruz board I bought off eBay for about £100. For me I haven't found the "perfect" board yet, hopefully the Capita DOA is it for me

I am by no means an expert rider, more of an intermediate/advanced rider
As noted by others, the winter is coming so it is mostly new stock at recommended retail prices .... you may find a bargain or two if you look around as some retailers want to get rid of old stock. The sale season for snowboard gear really starts near the middle of January onwards. Keep an eye out on eBay as usually some people want to get rid of boards at the beginning of the season.
As you are about to head out for your first real snow holiday I would give you some advice ..... take it cautiously your first few times down the slope. My last holiday was full of people who were "dome riders" (as it was a shop organised group trip) that hurt themselves (and others) as a real slope can be unpredictable with visibility being iffy due to lack of sunlight and shadows. Oh do buy yourself a helmet and wristguards (i would go as far as saying do this before purchasing a board!) ..... they will save you
