Don't rush out and get it all at once, you will make mistakes and end up with stuff you never use.
I will tell you what I use for my 10 mile each way commute and you can then have a think about if this will suit you too. I also don't have to cycle everyday so mix driving and cycling which is useful, as on my driving days I can take fresh clothes and towels to work ready for the cycling days. I have showers and a locker so start each day freshly washed in clean clothes.
I don't wear padded cycling shorts so have a mixture of walking/MTB type shorts and some running leggings for colder days. Eventually moved away from the tights type leggings to a slightly looser jogging legging as I get changed 30-40 minutes before the end of the day and walking around the office in tights for that last 30 minutes wasn't really appropriate. I'm not self-conscious so don't really care, but the looser pants do the same job without having to inflict the sight of my finely chiselled contours on the rest of my colleagues
Tops are a mixture of general base layer vests, sport tops and some MTB tops. Nothing roadie or aero for the commute (or any ride actually). As long as it is comfy, doesn't get too sweaty and can dry before hometime (then gets washed after one trip!), although anything will get sweaty on a 10 mile sprint/commute.
My favourite jacket ever is
THIS from
Decathlon. Great in temperatures below freezing with an extra layer underneath. apart from heavy rain it is my go-to commute jacket pretty much right through autumn, winter and early spring.
Gloves are tricky to balance warmth and dexterity, but without getting too hot and sweaty. I use Decathlon ones again, either cheap ski gloves or
THESE. Cold hands are about the worst thing possible when commuting in winter
For that biblical monsoon day I also have a full wet weather kit of breathable nightvision jacket, Endura gridlock over trousers and BBB heavyduty overshoes. It might sound daft but even when the conditions are at their worst you will still want to do the ride 'just because you can'.....
