Twenty bucks and my left kidney says that 90% of the people in this topic won't realize REO is trolling until it's been pointed out to them.
I've played Ermac and Cyber Sub since launch, since Ermac has been my favorite character since I was seven years old and Cyber Sub is just a concept I was really excited about from the moment Ed Boon hinted at it (which was like, the same day the game was announced). As much as I hate Tom Brady after his extremely childish and unprofessional behavior when I dealt with him for Mortal Monday, I'll admit that I picked up Sub because of him, and Noob in part. After he pumped up Sub, I decided to try him out, and took a liking to him immediately. I then saw him play Noob at Powerup, and I started to think "Wow, this character has better offense than I thought". I don't think his offensive ability aged too well once the game evolved further, but by the time that hit me, the character had grown on me and I'd taken a liking to his zoning.
I tried to pick up Sektor early on because I played Sektor/Cyborg Smoke in vanilla MK3, and since no one seemed to have any interest in the character, I thought it'd be interesting to try and develop him. I dropped him almost immediately, and it took me at least another month or two before he really clicked with me. He's one of my best characters now.
I picked up Cyrax because of various Cyrax players I saw at PDP, as it was the first time I'd seen any extensive use of the character. He's another character I didn't like at first, but seeing him used in high level play made me realize what he was capable of at the time.
I picked up Kung Lao because of Perfect Legend, more than anyone, but I learned most of what I know about him through osmosis because my training partner uses him. My Kung Lao isn't GREAT, but again, I learned him through osmosis. I only play him for fun.
Justin Wong inspired me to pick up Raiden, I'm not even going to lie. When I saw him play in pools at Evo, I was like "Alright, I'm learning Raiden". I'd never seen anyone utilize such a strong poke game with Raiden, and he used the teleport so seldom that it was like he didn't even need it.
Alex Valle inspired me to pick up Shang Tsung. Tom Brady did pump him up quite a bit, but it was Valle who really sold me on the character. I think he'd still be a top player in the scene if he'd really stuck with MK9, though I understand that he just doesn't have the time.
Milky Situation and Chris G inspired me to pick up Reptile, though he's also another character I just play for fun. I don't take him too seriously.
That's about it, really. I can't think of anyone else off the top of my head that I was particularly inspired to play by someone else. Xblades has inspired me to look at Liu Kang more in-depth recently, but I haven't really "picked him up". REO inspired me to pick up Mileena for awhile, but I never really stuck with her.
Since I'm sure someone will wonder about this, I picked up Skarlet sometime around July because no one was playing her. No one knew ANYTHING about the character, so I wanted to explore her and see just how good she is. That's all there is to it. I also picked up Kenshi and Rain at launch for no reason other than Kenshi wound up being really fun to play, and Rain was one of my favorite characters as a kid and I loved his redesign. Ironically, he bores me to fucking tears when I actually play him, which is really disappointing.