Recommended DRM-free HOG's at GamersGate:
This
<span class="bold">Alawar 5-in-1 pack</span> is an excellent deal. I've played and enjoyed 3 of the 5 games, and the price is worth it just for those three.
*peruses some more, then gives up on linking them all*
They have a BUNCH of great IHOG's, including some of my favorites! I have reviews for all of these (and recommend them):
Brink of Consciousness - Both games are EXCELLENT, and in different ways.
Forbidden Secrets: Alien Town - Another one of my favorites!
Cruel Games: Red Riding Hood - While not as polished as those above, still really enjoyable.
The Gift - This one really deserved more attention than it got. There are some flaws, but overall it's definitely worth getting.
Dark Arcana: The Carnival - As mentioned by Hypersomniac, this is REALLY a good game.
Twisted Lands games, all three of them - Some would disagree on this, but the "What the hell?!" moments really worked for me, and I loved them all.
House of 1000 Doors (only have a review for the first one) - Excellent production values on this series
Mountain Crime Requital - This one surprised me, as I didn't expect to like it, and it ended up being a favorite.
Stray Souls series - I adored these games! Absolutely excellent!
Nearwood - One of the best IHOG's of 2013! This one came in second place for me, right behind the CE of Nevertales, and tied with Enigmatis 2: The Mists of Ravenwood... Hmm, and Stray Souls 2! lol~
That's probably enough of a list for now :D