It is of course a tough call - look good enough to nip into the cafe or lunch, yet walk and stand all day whilst feeling warm and comfortable in cold, snow or mud. If you do a fair bit of walking, standing or driving in them, you need something that has a comfortable footbed with a steel/fibreglass shank between the heel and ball of your foot. Otherwise your feet will be tired in no time. If you can, take the boot in your hand, put one hand cupping the heel where it hits the ground, another hand at the toes, and try to bend the toes towards the front of the ankle. If the whole sole of the boot bends like the letter U, you will have tired feet in no time and no support in snow or mud! It should be stiff between the heel and the ball of the foot, then from that point forward it should bend so that you can move the toes when you walk.
Secondly, wellies alone are NOT suitable footwear in any kind of cold weather, since they ooze coldness. Even with all kinds of polyester fleece wellie warmers which are commonly used here. I'm originally from Finland, so I should know about keeping your feet warm...so read on...
In my opinion you have two options as discussed in the previous threads: either waterproof lined leather country boots or neoprene lined wellies. Both are warm, and great in the snow and mud, as long as there is good enough tread in the sole and enough insulation.
Neoprene lined wellies are a great easy maintenance option, though make sure your neoprene is at least 4mm thick, otherwise when it snows or even at lower temperatures when you're not walking, you'll get cold feet. Some companies like Hunter mostly fob you off with 2.5mm which is nothing. Neoprene is very comfortable, warm and cushioning, and many people compare their neoprene lined wellies to their favourite slippers, and wear them all Winter pretty much every day. You should not need any kind of thick socks either so you can get your normal size and not look too clunky.
Country boots are great too, treat the leather first with a spray-on "leather and nubuck waterproofer", and repeat this periodically on cleaned and dry boots to make sure the leather doesn't stain from all the mud. The boot itself should have a breathable and waterproof lining anyway, so you're not doing this to waterproof the boot itself but to keep the leather looking good for years to come.
In my experience and recent research on wellies (my last pair of cheap £10 wellies broke in 4 weeks) if you want warm all day comfort that will last for years, invest in Aigle Parcors ISO 4.5mm neoprene lined wellies (I've got mine in the post as we speak!). There sincerely is not a single soul on the internet reviews who is not exceedingly happy with their comfort and quality, including hard core dogwalkers who cannot wear them out in nearly 10 years of serious use. You can now get them for £95. Under any circumstances, if you're on a budget like me, don't go Hunters because of what I've read about their quality since they moved their production to China. Hunters will last you three months, you spent £70, need I say more? Nobody can afford to keep buying cheap (or expensive) wellies that do not last more than a few months. I got my Aigle Parcours ISO's on Ebay very little used for £69 and can look forward to 10 years of walking, standing in the play park, and warm happy feet. They look pretty sculptured, but I wouldn't wear them with a skirt!
I also have a great pair of Joules waterproof lined leather country boots. Whilst they are no longer available, I can vouch that much like the very expensive Dubarrys do on all their marketing outings, I'd happily stand in a very deep cold pond for the entire afternoon in them. One complaint and caveat on the leather country boot though: make sure it has the shank in the sole, and a comfortable, ideally anatomic footbed. That way you can walk and stand for hours. Mine don't have it, so can't do long walks. But they look great with a skirt or a pair of jeans.
I read from the review world that the winner in wellies for winter seems to be the Aigle Parcours ISO with over 10 years on the market, and as for the country boots, many people swear by Dubarry but the horizontal stripes are going to make your legs look short at £300, there's the Ariat Grasmere at £200 but look at the design which makes your legs look rather fat, so why not try Dublin Pinnacle at £110? Just like the others they have the waterproof lining, shank, good footbed, great looks, and are adjustable in the calf for when you have less or more legwear or put on or lose weight. They even look good enough to wear with a skirt. If you're not doing 8 hours of horses every day like some people who buy them and complain they don't last the long term, the hours of daily battering may not be relevant to you and at a third of the price of Dubarry you should be getting an extra Christmas card from your bank manager for not overspending! And you can have happy warm feet all Winter, look good, and have very little maintenance. Just do a Google search for Dublin Pinnacle Boot Review, like you should do for anything else you consider buying. The answers speak for themselves, especially for Aigle ISO.