I look forward to checking these out- much less investment than an entire series, and a few I'd never heard of.

A few more came to mind:

Princess Principal: Wonderful opening episode that is actually quite representative of the rest of the series. A joy to watch and share.

Death Parade: Tightly constructed and paced perfectly. It actually makes the second episode (which is actually good) pale in comparison.

Planetes: Introducing the audience to the debris section couldn't have been handled better or more entertaining, I would argue. Superb visual world building and a strong self contained plot on display.

Full metal Panic Fummofu: Excellent pacing for gags both dialog and visual driven.

Zankyou no Terror: Again, not the whole series, but this first episode sold me on finishing it out, for better or worse...