Overclocked: It is just as tense and dark as Still Life but with a much better developed(and imo more interesting) main character. I could aso strongly recommend the Sherlock Holmes series by fragwares
Sherlock Holmes: The Case Secret of the Silver Earring
Sherlock Holmes: The Awakened
Sherlock Holmes vs Arsene Lupin/Nemesis
Sherlock Holmes vs Jack the Ripper
Also if you're in for a brainless clichéd fun ride you might wanna give the Art of Murder series a try
Art of Murder: FBI Confidential
Art of Murder: Hunt for the Puppeteer
Art of Murder: Cards of Destiny
If you're looking for more Broken Sword style games I hinghly recommend the Secret Files series
Secret Files: Tunguska
Secret Files 2: Puritas Cordis
I can also recommend
Secrets of Atlantis and
Chronicles of Mystery: The Tree of Life
Of the indies I higly recommend the Ben Jordan series (from case 3 onwards)
Case 3: The Sorceress of Smailholm
Case 4: Horror at Number 50
Case 5: Land of the Rising Dead
Case 6: Scourge of the Sea People
Case 7: The Cardinal Sins
And the blackwell series
The Blackwell Legacy
Blackwell Unbound
The Blackwell Convergence
And you've probably allready played them but I'd never forgive myself if I didn't recommend these
The Last Express
Gabriel Knight: Sins of the Fathers
Gabriel Knight: The Beast Within(heard it's good haven't played it yet)
Gabriel Knight: Blood of the Sacred, Blood of the Damned
That's all I can come up with for now