Here are some of my essential riding staples -

Smartwool socks - I can't ride without these. I look for deals online at places like sierratradingpost.com and backcountry.com.

Arm warmers are a must for me, on rides that start out chilly. I have a pair of Craft arm warmers and I love them. Soft, smooth fabric with a slight bit of compression in it...they're warm and stay put.

Toe covers - I use the Pearl Izumi Cyclone toe covers...got them at my local REI store for around $20. They block the wind and cold from getting into shoes...especially ones that have a lot of vents for cooling.

Tights - I got a great deal on a pair of Sugoi Sub-Zero Tights from Backcountry.com. I paid $39 for them, and they are super warm! Nice material, ankle zippers, lots of reflective material, and a good fit. I'm very happy with these tights.

Suspenders - might sound strange to most, but a friend turned me on to this one. On colder rides, when I'm wearing tights over my cycling shorts...I was always having issues with my tights slipping down my waist. Most of my cycling shorts have a rather slick/slippery feel to them, so the tights on top of them tend to not stay in place because of this. I got a pair of cheapo suspenders from Walmart, and problem solved. My tights no longer slide down, and I don't have to constantly yank them up while trying to steer with one hand on the bars (something I'm not very good at).

Windbreaker jacket - I recently picked up a Canari Touring Jacket from REI. At first, I thought the flimsy material wouldn't do much...but after wearing it on 4 windy/chilly rides, I have to say that it does a decent job of cutting the wind. I got the jacket in a Hi-Viz color...this thing is BRIGHT! It fits well, has 2 side and 1 rear pocket, a nice fleece-lined collar, has zip-off sleeves that convert it into a vest, and it stuffs down into a fannypack so you can wear it around your waist if it gets to hot. I paid up for mine ($70), but I have seen this exact same jacket on sierratradingpost.com going for around $30...which is a STEAL!