My return to active roleplaying was Warhammer 40k - Dark Heresy. That was probably 2007 or so, using Fantasy Grounds. I'd been away from active RPG playing for about 10 years at the time, and Warhammer 40k and the Fantasy Grounds VTT were my first steps back. I have very fond memories of the time.
As for Warhammer 40k - Rogue Trader, I always felt of the various flavors of the 40k mythos to roleplay in, it would have the most flexibility.
Looks like I'm picking up another Humble Bundle RPG bundle ;)
The Minotaur for Old-School Essentials
*Requirements:* Minimum STR 9, Minimum CON 9
*Prime Requisite:* STR and CON
*Hit Dice:* 1d10
*Maximum Level:* 8
*Armor:* Leather, including shield...