I'm not sure what your price range looks like, but If you got the cash, Osprey is a great company. The Kode series specifically is what I would recommend. Ive owned numerous different packs from them. And whenever I have busted a buckle they have shipped me multiple for free. They have even shipped me lost straps and other stuff that they had no obligation to replace.
Depends completely what you are looking for. If you think you are going to be mostly skiing slackcountry with some lift access I would say you don't need more than about 20-30 liters, however, if you are thinking about going for long tours you will want more space. I like north face and ortovox packs but there are a ton of cool companies out there. I would look for something that is made of a rugged waterproof material and fits the size you are looking for.