I am sure others have mentioned the Trilliums and Tree Houses of the beer world, and they should be if we are talking IPAs, but in my opinion they do not do much else that stellar. At least Tree House does not. I cannot speak to Trillium as I have only had their IPAs.
With that said I have really only been drinking CT beers for the past year and for a small state there are a bunch of very good breweries. Not sure if anybody has mentioned Kent Falls, but I think they are the best brewery in thd state right now. They put out a bunch of different styles and do them all pretty well and I do not see many other breweries messing around with gose, saisons, sours, and farmhouse ales. Their IPAs are solid too. Not on the Tree House/Trillium level (not many are) but they are very good and you do not have to wait in lines for them either at the brewery or store.