I have a shanty also, its a definite deal breaker without. Its nice because it keeps you outta the wind and gives you the option for complete dark so you can see down the hole better. I once went out with a shanty that did not have a floor and froze my ass off. When i bought mine, it had to have a floor.
As far as what they are hitting on- Mostly minnows but i always bring wigglers and spikes out there as a plan B and C. Hell, there have been times where they hit on an empty hook! Most people are here are pulling Perch, Crappie and Pans but there are a lot of Pike in the area so there are some people that take advantage of those also. I actually just bought a tip-up this week so im curious to see if i can get me one of those toothed critters next time i go out.
I got into ice fishing only a small handful of years ago actually. I first went out without a shanty and still found excitement in it even know i never caught anything. In fact, my first 2 seasons i did not catch ANYTHING. There was even a season that i did not have an auger and had to spud my holes out which took A LOT of work, but it never stopped me. I used to have to wait for people to come out with me because i did not wanna go alone, but this year is different. Its like pulling teeth to find people to fish with, at least im my group, so now i go alone. I find myself going once or twice a week compared to once or twice a month.
To me, the winter is a miserable time and with things like ice fishing and snow boarding, they keep my mind occupied. If i did not have those two things to do, ya better hide the razor blades!