Tin Pot
Guru
I have a Castelli Alpha jacket and like it, so much so I have two of them. If you wait until after Christmas and by that I mean probably literally just after Christmas, I expect they will be on fairly heavy discount from Wiggle et al.
The other jacket I have is a Castelli Espresso, probably not quite as race / close fit as the Alpha, but a good jacket nonetheless.
Baselayer, I wear a merino - Icebreaker Oasis, I have four of them, two crewe neck and two higher neck with 1/2 zip.
I was wearing the Espresso and Oasis last night and the Garmin read -3.7c, we were not going fast not not generating much heat, but I wan't cold.
For colder days <5c I wear Castelli Sorpasso windproof bibs. The only way cold weather with stop me riding is down to ice, as the clothes will keep me warm enough.
I would like some new bib tights as mine are getting to the well used point, but can't bring myself to pull the trigger this side of Christmas on a new pair. I'll wait until the sales...
I think I'm settling in that approach, I'll be lucky to get in three days riding before Christmas even though that's 12hrs, I survived last year.
I'm thinking the Espresso is looser, and with my waistline I'll go for that if it's discounted. Otherwise an Alpha, or a Sportful Gruppetto Partial or Fiandre WS.