Nearly always online, usually as part of a Steam sale. Same for console games too, if it was a day one purchase I used to buy in store as the prices were generally the same for the first few weeks after a big release, but now that's changed.

I got Final Fantasy X/X-2 HD for about £22 online (it's £30+ in stores) and The Elder Scrolls online for slightly less, if the difference was minimal I'd still buy in store but when the savings are nearly always £8 or more online will always be the way. And occasionally I'll get the game the day before it's official release date, so there's really no need for me to buy games from specialist shops anymore.