Are we talking recently played games or games you find yourself playing more of than others?.
Because I dunno how to do "top" games on Steam but do know how to go for Recently played =P.
Also I'll probably add that I play Battlefront and Red Alert 2 daily, on Battle.net some SCII Legacy of the Void (need to get back into Heroes and Hearthstone), GoG I'm going to go with Fallout 1-2 sometime this month or the next.
I'll upload a screen of my Steam list of recently played in a while but I dunno if I should add my entire library even though I have quite a few games not yet installed.
As for my fave store client vendor I'd have to say Steam with battle.net being a close second for it's polish and style (not being cluttered either) with GoG Galaxy and Origin tying for 3rd place (Uplay will forever be garbage to me).
Step right up come on in, feel the buzz in your veins, I'm like an chemical electrical right into your brain and I'm the one who killed the Radio, soon you'll all see
So pay up motherfuckers you belong to "V"