We're a couple of days late with this, but I felt it really deserves a mention. Spiderweb Software, the studio that creates classic isometric RPGs, has just celebrated its 20th birthday. There aren't many studios that can claim that, especially with the original team still working there. Of course, it helps that the original team is Jeff Vogel.
That's not quite fair. Regular contributors like Andrew Hunter, Linda Strout and Mariann Krizsan have been with him along the way, but Vogel is the core creator behind 21 games over 20 years. Games like the Geneforge series, the Avadon run, and the Avernum roleplayers. And the 21st is Avadon 2: The Corruption, due sometime later this year.
Recently Spiderweb have found broader success by releasing their games for tablets as well as PC/Mac, and I can testify to their excellence on both platforms. It's tempting to describe the games as "hardcore RPGs", but that never feels fair. They're "classic RPGs", born of a world where Ultima ruled, never feeling the need to abandon a simple aesthetic and interface, while offering extraordinary depth in story and exploration. Just the written content alone makes his one-a-year output absolutely remarkable, let alone that it appears in engrossing games.
Most of Spiderweb's games are now on Steam, at far more sensible prices than their own peculiar webstore. You can pick up all of the games in one go for £30, or individual games for between £4 and £7. Which is an awful lot cheaper than the odd $15 to $20 that Vogel charges directly.
If you're looking for somewhere to start, I strongly recommend picking up Avernum: Escape From The Pit - a remake of the original Avernum game, as well as the first in the new series, Avadon: The Black Fortress. Both have provided me with oodles of hours of entertainment, and I dip back in pretty regularly.
There's a splendid timeline of the last twenty years of development right here.