Way to go and welcome, Spikybreak! Just ran across this thread. Though I've not managed to commute by bicycle, I am a bicycle tourist, meaning I share a lot of interests with commuter types.
Among other things, winter riding. I live in the US State of Colorado, which gets a fair amount of snow in the winter. I have ridden on studded tires every season for the past 5 or so winters, and I love them. Mine are made by Nokian, the model Hakkapeliitta W240. The number stands for the number of carbide studs in each tire - 240.
Other models are available with ~110 studs per tire. These are naturally lighter, but only suitable for smooth ice vs. frozen ruts and foot or vehicle-churned, re-frozen wastelands. Since I ride both on and off road, I went with the higher number of studs and have never looked back. There are also some models available with 300+ studs which claim suitability for use on frozen singletrack.
Between the studs and the low-temp rubber, my tires' traction is flatly unreal. With them, I've ridden up and back down ice-covered hills I'd hesitate to attempt on foot. I've ridden through mile after mile of snow, relishing the distinctive crackle of carbide studs on ice as I passed over hidden icy spots with nary a problem.
I've ridden over frozen patches marked with warning signs which could easily have served as skating rinks. I'd have walked around, but I rode straight over without a second thought thanks to the studs. The only reason I haven't been out bicycling the local frozen lakes in the winter is that I'm the only one I know who's crazy enough to try it, and playing on ice is the kind of thing where you really need a buddy available with rope and the like, in case things go wrong.
It's critical to remember that when you're bicycling in traffic on icy roads, the fact that you have traction
does not mean the cars around you have it, too. It is all the more important to have a rear view mirror of some sort in the winter, and to be even more aware of the traffic around you. Cars may slide into you from behind or the side. I've seen them break traction in this way at random, though not usually while bicycling. If you're in the saddle, it's well to have contingency plans for what to do if you stop and the car behind you proves unable to do so. Same thing for if the guy passing you abruptly breaks traction with the result that the car comes at you laterally, or from the side, without any warning.
In practice, poor road conditions seem to inspire most motorists to pass more slowly and with more clearance than usual. I usually feel safer on the roads in winter than I do in summer. There are always exceptions, of course, and though I believe I could find Latvia on a map, I'm sorry to say that I otherwise know very little about it. Drivers there may respond very differently than ones here.
In any event, I ride a so-called expedition bike, which is basically a heavy-duty touring bike designed for both on and off road use. It was designed and sold by a domestic company called Novara which has since changed its name to Co-op. I'd definitely recommend it - the model was called 'Safari', except for the fact that it's likely hard to find outside the US, and the wheels are likely a bad fit for your locale.
My Safari rolls on 700x42c wheels, which I understand to be hard to replace outside of Western Europe and the US. If that is the case for you, I might recommend looking into Surly brand Long Haul Trucker bicycles. These are available with either 26" or 700c wheels. Based upon what I've read, I'm guessing you'll have better luck with 26" (classic Mountain Bike or MTB) wheels than with 700c come time to find spares and replace parts. I may certainly be wrong, though. What types of wheels do you ride out that way in terms of size? If both are available, it's maybe time to talk advantages and disadvantages. If not, the choice is simple

.
Regardless of the size of your wheels, I definitely recommend the use of full-coverage fenders. They not only catch snow, ice, and mud, but even seem to cut down on dust when I play on dirt roads. I especially like rolling through muddy, half-frozen slush at speed without having to taste or wear it. Bear in mind that your shoes will still catch spray, so shoe covers or some other moisture barrier are a wise choice. If you ride through more than ~4" of water with any speed, your lower body will get soaked. Slow down a bit, and only your shoes are likely to get wet.
Others have covered flat and drop bars. You also have the choice of so-called
trekking or butterfly bars, which offer multiple hand positions like drop bars, but in a completely different configuration which is more suited to playing off-road. You may also want to look into the
Jones Bar.
Are you new to cycling, or looking to enjoy it in a different way? Either way, I wish you all the best in finding your perfect ride, and enjoying it!