What zeratul said. Although personally, I always try to check the library for stuff I just want to casually check out, too. 
(although netflix has, too!) I didn't think I'd get into it either, having come across a couple re-runs of the 'classic' series and found them strange (granted, different style of tv back then!), but the concept was always great, and when they rebooted it all polished up a decade ago, been a fan ever since.
Mark did some fun ones, but I don't usually think of them when recalling 'awesome episodes'. Now Moffat's, on the other hand, if you're just looking to lightly browse the familiar writers… wow. He was quite a different show-runner than the previous Russell Davies and tended to have more series-story-arcs (which is why it's trickier at times to jump into some of the recent ones). But he had a knack for creating some of the best monsters. Joke that thanks to him, Whovians are (amusedly) 'scared' of stone angels, the dark, creepy snowmen, weird wi-fi sources, gas masks, and marks on your hands/arms (a joke referring to the Silents creatures)
You also named one of my top five favorites…. Wasn't 'Fireplace' beautiful? That's the kind of stand-alone story with the perfect mix of DW themes of the effects of time travel/the kind of life he leads, scary creature, production style, and companionship/adventure. 'Blink', 'Midnight', 'The Eleventh Hour', and 'The Doctor's Wife' (written by the well-known Neil Gaiman!) also knock it out of the park in that regard.
Glad you enjoyed!
