x3 for the wiggle/dhb stuff. There is a lot of exotic gear out there but if you're looking for good basic thermal fleece stuff it's great.

For those temps I'm usually in a medium fleece baselayer and either a thermal jersey or thermal vest.

If you can splurge for fleece bibs they are also great, but usually those are 40 and under for me.

Don't ignore the accessories either. A cheap buff adds a lot of core warmth. A quality hat is also helpful. I like Giro' seasonal wool or heavier offerings.

Wear it is really cold, people have a collection of long sleeve jerseys ;-) But you can get windstopper underlayers in short sleeve and they work great with warmers. I'll wear one even when it is going to get up into the high 60's if a ride is starting out cool. I really don't like cold wind on my chest!

I'm not a fan of long sleeve jerseys. In my opinion they are either not warm enough or never fit me well. Either big and baggy or the sleeves come about 3 inches too short.

50s:
arm warmers
knee warmers
wool socks
toe covers
base layer
jersey/bibs
long finger glooves

40s:
arm warmers
leg warmers
thicker wool socks
shoe covers
base layer
jersey/bibs
wind vest
heavier long finger gloves

I like Defeet socks, kneekers, and arm warmers.
Castelli nanoflex and gabba can cover you for a lot of temps/conditions.
Wool base layer shirts can also cover you a lot of temp ranges.

FWIW
Up here in Seattle, it gets cold and wet and stays that way. My favorite piece of gear is definitely my Ibex wool bib knickers.They keep you warm, block the wind and wick great when it rains. If it gets sunny and 'warm' you won't sweat profusely. No need for knee warmers. If it gets really cold, then I simply wear a pair of tri-short under the bibs.

Up top is subjective I think - we all run at different temperatures but arm warmers are a nice option if you start to get too warm - simply roll them down.

Rubberized shoe covers are essential up here as well. Two pairs: 1, thin rubber (rapha makes the best one IMO) and 2, Neoprene and thick for really cold days.

Finally, own a couple of different gloves: 1, waterproof and 2, warm (for dry days)

I’m built like a giraffe and had this problem too, until I started getting custom jerseys with a couple extra inches in the wrist.

There is nothing in the world better for cold hands than neoprene gloves. And they don't even have to be fancy cycling ones. Kayak gloves are in nearly every way identical to far more expensive cycle branded neoprene gloves, just without the logo.

Riding in pissing wet and cold West Yorkshire is almost bearable with neoprene gloves.

Tend to wear a long sleeve base layer with arm warmers on a really cold day, anything under 5 deg C whatever that is in weird farenheity stuff. The beauty of arm warmers is you can just roll them down if you get a bit warm, for longer climbs.

PS as others have said, dhb is very good for the money. I use the bib shorts quite a bit.

That said I am very partial to my Sportful fleece lined long sleeve jersey. It is a thing of great beauty, although it is the first time I've had to buy XL in cycling kit. Italian men must be TINY.

Rich.