After buying an absolute load of gear, if I was starting out again I'd keep it simple, robust and effective:
For winter walking, most important layer is your base layer - it needs to fit well, merino wool works well but some prefer synthetics. This keeps your skin from getting too clammy, and since water conducts 20 times better than air, this is what causes you to cool down rapidly in the winter months. Above that - 100wt fleece is what I use in much of the winter since I find it cheap, effective and I don't much care if I snag it on a barbed wire fence. I've got a Polartec Thermal Pro beefy winter fleece which is exceptionally warm but not effective for moving quickly or uphill, so this usually works best for a winter ambling around town item or I leave it in the car as a dry layer for when I finish.
Windproof above the fleece (good ones are much more breathable than waterproofs, meaning less clammy, less wet, therefore less cold), but if you want a waterproof jacket that will be fine. Pick something you're happy to wear for hours and I'd always choose pit zips if available as well as an adjustable hood which won't be useless in high winds.
I keep a Mountain Equipment synthetic belay jacket in my rucksack for the winter months which is oversized and can go on top of everything else. It works when wet, when I'm absolutely freezing and I find I prefer a simple warm jacket instead of taking layers off and 'adjusting' everything else. This also works as a good 'loan' layer if you're hiking with anyone who is struggling since they can hand it back to you after warming up without taking everything off and losing heat.
Overall - good base layer (£20), 100wt fleece (£20), waterproof (£60?), warm jacket (£50?), good gloves and a hat. In general I walk in base layer + wind proof and a light pair of gloves for most of the day, but then again I walk quickly and put out a lot of heat.