Wow, good question. But a complicated one. There are so many choices. How cold do you intend to ride in? Freezing? Around 20 degrees? Colder? Cycling is hard to dress for because you have wind chill at speed, then can easily overheat when climbing.
Layering is the key. When its in the 30s, I start with a midweight long-sleeve jersey or top, such as REIs Midweight Long Sleeve Crew ($30). Maybe throw a regular short-sleeve jersey over that for a little extra. Over that I like Pearl Izumis Zephrr Jacket ($75). Midweight tights such as the Louis Garneau Vello Thermal Tights ($70). And midweight glovesI recently referenced the Manzella Silkweight Windstopper Gloves ($30) for a guy going to Everest, and they also are what I wear when it is chilly on a bike. Great gloves.
When freezing down to 25, I like a little heavier pair of tightsPerformances Radiator ($60) are a great buy in a very warm tight. For a base layer, I swear by woolIcebreakers BodyFit2 60 Crew ($80) is dynamite. Over that, if dry, the Zephrr. For gloves, maybe the Gore Bike Wear Mistral III ($50).
If its really cold, then a wool short-sleeve T under the long-sleeve T like Patagonias Merino 2 T-shirt ($65) adds a lot of warmth. A beefier jacketthe Showers Pass Elite 2.0 ($230), which uses eVent fabric so its great in the wet too. Pants? Pearl Izumis Amfib Tight ($100), which are windproof and lightly insulated. Pearl Izumi for gloves, too, their Barrier Lobster Glove ($70), which are waterproof and insulated.
Ive biked in the low 20s with basically Combination Two. Youll need to experiment a bit and see what works. Once youve got some trips under your belt, you can start to fine tune your gear in five-degree increments.