Essential cycling kit

My essential kit is a Helly Hansen Lifa Dry base layer. Its ace and I wear one for at least 6 months of the year. I have tried loads of base layers and I always come back to these.

There is some good value bits and pieces here http://www.cycle-clothes.co.uk/all-products/?type=road-cycling
The tenn overshoes are perfectly good and their bib shorts are good too

The kit that gets the most wear for me in the off-season are:

--Long sleeve baselayer top (Castelli Iride): great moisture wicking so my skin stays dry and it's easier to stay warm (your outer layer/long sleeve jersey or jacket will get wet from sweat wicking out). Similar principle in hot weather but with a thinner mesh sleeveless baselayer, wicks sweat to the surface so you can continue to stay cool through evaporation. Need to be good about hydration though. (Castelli core mesh sleeveless base layer--reviewed on road.cc http://road.cc/content/review/87361-castelli-core-mesh-sleeveless-base-l... And yes, your partner may choke to death on their tongue while asking you if they come with tassels but you can laugh yourself off the saddle when they're prostrate from heat stroke halfway into the ride)
--Windproof winter jacket with thermo or super roubaix insulation and torso zip vents for when you get hot on climbs (Giordana Forma Red Carbon jacket)
-Wind vest for spring/fall when just a jersey is too cold but too warm for a jacket
--Bib knickers with windproof and thermo roubaix insulation panels, it's mainly 0-10C where I live in the winter so although I have windproof, insulated full length bib tights I find that I almost never wear them as they're too hot for the milder winters we have (Capo Padrone bib knickers). After having switched to bibs over shorts/tights I will never go back. They stay in place so you can forget about them and don't dig into your waist when in the cycling position/waistband doesn't roll over and drive you insane while you're fiddling around trying to surreptitiously yank them up.
--Windproof, water resistant, insulated gloves with silicone palms for sure grip even when your bars are wet. Hard to shift/control the bike when your hands feel like blocks of ice (Castelli CW 3.1 gloves are so warm I can't wear them if it's warmer than 7C and I tend to run cold. They also can activate touch screens although I find the contact point is rather finicky. When it's above 7C I love my Castelli Lightness gloves--water repellent with light thermoflex insulation and lots of dexterity. Almost no padding which I prefer but might be uncomfortable for some.)
--Wind and waterproof shoe covers keep my toes toasty and dry.
--Thermal headband to keep the ears warm. Makes a huge difference for me in terms of comfort and perceived warmth (Castelli Viva thermo headband)

While I do have a waterproof cycling shell, I rarely wear it even though it rains throughout the winter here cuz while they keep the rain from getting you wet, they don't breath well so you end up steaming in your own sweat so different kind of wet

I have expensive kit but except for the shoe covers (never been able to keep a pair alive longer than a season), they should last years unless you crash. I'm also small so I fit Euro whippet sx or small kit which usually gets heavily discounted

Aldi compression base layers are fab! I usually think you get what you pay for but there base layers are as good as ones I have payed four times as much for.

I bought a pair of DHB Vaeon Zero bib tights for this winter and they have been awesome. A nice windproof panel on the front covers the shins and thigh offering good protection.

Arm warmers with s/s base layer under long sleeve jersey provide options and then a fantastic Rapha gilet to keep the top half warm.

Endura neoprene shoe covers and sealskin gloves complete the winter get up.

A windstopper jersey is a great thing if you ride in the cold or do long descents. Just bought a windstopper base layer, clever thing.
The nano flex castelli arm and knee warmers are fabulous.
Buy the nicest bib shorts you can find and do try them on, so much more comfortable than plain shorts. Try on a few brands and get the fit right, it should be comfortable in a bike shape and perhaps a bit tight when stood up, don't get it too big around the waist, as it will shift about. You might be different sizes in bibshorts and tights. I'm a medium in castelli shorts, but a large in 3/4 and tights, due to leg length.
I also really like the craft sleeveless mesh base layer, very comfortable, these should be close fitting to work properly.

I've used two of these dhb long sleeve windslam jerseys for the winter (http://www.wiggle.co.uk/dhb-windslam-roubaix-long-sleeve-jersey/), and unless it's raining heavily, they've stood up to a Glasgow commute.

They're pretty warm, and the windproofing on the front means that I really don't feel the need for a softshell or anything over it unless it's for some serious waterproofing.

Also, I'd recommend getting really good boots and gloves for the winter. Warm hands and feet are essential for me, so I got some Specialized Defroster boots on sale, and I wear Castelli Estremo gloves. Both are great.

Hope that helps.

My two essential recommendations are good quality baselayers and a gilet(vest).

I initially used compression baselayers which were okay but this winter I have been using a long sleeve merino wool baselayer and it's fantastic. Not only is it warm but the problem of overheating and sweating during a winter ride is a thing of the past. Next on my wishlist is one of Castelli's Flanders baselayers.

I was dubious about buying a gilet but it bridges the gap between wearing a soft shell jacket and summer jersey. I now have two, one which is more of a windstopper and which is use for early morning cycles and the other is which is a packable waterproof one which I carry in case the weather changes for the worst.

I'd get a baselayer, it lengthens the duration in which you can get away with the jersey & armwarmer approach. These needn't be expensive.

As far as longsleeve's concerned, I usually have a soft longsleeve so I can layer up for super cold days (base, jersey, armwarmers, soft longsleeve) - always handy, and you can always ditch one of those layers for the in-between.

I don't actually own a softshell. I have a hardshell high vis for when it's REALLY bad/night time winter riding. Instead, I find a windblock covers better ground, in that while you're always inevitably going to get wet if it's raining - it's better to keep the cold wind out to stop said water freezing you. Windblocks generally keep out a spot of rain anyway.

Winter socks - you only need a couple of pairs of merino badboys, defeet or sportful do really nice and relatively cheap ones.

Don't get me started on oversocks though, I have an addiction, I have lycra for the summer, wool/belgian for early autumn/late spring, neoprene for greasy days and then full on industrial scale weatherproof ones for winter.

It is really confusing, I did my first winter on a bike last year and probably definitely didn't have enough on. Saying that I got by quite well this season without spending much.

OOH if you can afford do try some of the sportful or castelli "anti rain" leg and arm warmers. again a good mixer for most seasonal change. I've got through a northern winter this year with JUST shorts and legwarmers (it helps to use hot balm underneath!)