Well for me it's the series that got me started:
Secret World Chronicles http://www.secretworldChronicles.com
It's modern day take on superheroes after an attack by ......well the story is ongoing(slightly stalled) and co-created by Author Mercedes Lackey
a good site is also
http://www.podiobooks.com has a good selection including (where I discovered seasons one and two of DRT. a few Gems:
Space Casey by Christina Ellis an sci-fi comedy that has to be heard to be believed.
Playing for Keeps by Mur Lafferty. A great take on superheros or heroes who happened to be super.(she has several different series)
Shadowmagic by John Lenahan a fantasy journey with an celtic flair.
MEME by Rob Lowell another that stands out on it's own.
and the "Share" trilogy by nathan Lowell which is a young man's Sci-fi Journey. as he matures in space a totally Story driven series and part a greater whole as they are all linked. (still on-going)
there is so many to list and the author still gets paid...(They Have links to the original side if you want to cut the middleman out and find more info on the author and series.