RPG systems you liked -- much to your surprise

[Jackelope King]

Even after the horror stories I'd heard about superhero games, I gave Mutants & Masterminds a shot, and now the only problem I have with the game is trying to find a copy of the new edition.

Cyberpunk 2021 was another pleasant surprise. Not the greatest game in terms of mechanics, and after hearing the premise I shuddered a little (80s angst transplanted 40 years into the future), but the genre grew on me quite a bit, inspiring me to get more into it and actually check out Ghost in the Shell and the like.

 

[Maliki]

It wasn't much of a surprise, but I really like Castle and Crusades siege system.

 

[Mustrum_Ridcully]

For me, it was definitely D&D, 3rd Edition. I came from playing Shadowrun and could never imagine enjoying a class and level based system using hp and a crude spell slot system.

Today, D&D and the D20 off-shots seem to be best available system and we rarely play a non-D20 game.
The longer I digged into the system, the more I understood it, the more I saw how well thought out the concepts were and how well everything interlinked. (Well, that doesn´t say that there aren´t a lot of weaknesses, too...)

 

[Professor Phobos]

Cinematic Unisystem. I was...well, knocked off my feet. The game is, for my purposes, perfect, if a little short on the options (which Beyond Human will solve, in time).

I was also impressed greatly by Warhammer FRP.

 

[HellHound]

The most recent one for me is WHFRP2

I learned to hate WHFRP years ago after playing and running campaigns for almost 2 years. The system was buggy and had too many holdovers from WHFB. I just finished reading the core book of WHFRP2 and am 100% in love with it. Totally hooked.

I'm now in the process of changing / modifying the careers and magic system to run WarHammer Fantasy DiscWorld.

 

[Psion]

D&D 3e.

I had seen the playtest rules and was totally going to keep steaming ahead with my house ruled 2e variant and/or Hero

Then I saw the MM. That inspired me to try it. I started a second group to try it out. Within a month, I converted the campaign for my first group to 3e.

 

[Dagger75]

Mine was Angel. I really liked the game and the system. I'm not a big Angel fan, actually only watched season 5 but I still really enjoyed the system.

Runner Ups:

Feng Shui
Hero 5th Edition

 

[AdmundfortGeographer]

WFRP2. I didn't think a system so chalk full of countless "careers" and easy death could be fun. No, I had zero familiarity with WFRP before 2nd edition came out... that it was authored by Chris Pramas got me to even give it a glance...

RuneRPG. Based on the computer game, the RPG uses a system derived from Ars Magica 4th edition. Didn't think a system so focused on troupe play and spellcasting could do double time perfectly for a competitive melee combat game.

 

[Quicken]

These might be a bit old but anyway...

Mechwarrior - I was presured into GMing a game of this (I didn't even know the rules at the time!) and it ended up being a lot of fun. Combat outside of mechs was very deadly and fun to play out. Although admittedly it scared the crap out of my players. Not many games I've played where people have yelled "He's got a gun! A pistol! Look out!!!".

Rifts - I already knew all the problems with the rules and thought the setting was derivitive crap. But when I actually played it I found the setting was much better than I thought. We house ruled a few key things, made every choose 'balanced' character classes and suddenly the game was not just playable. We were having fun!

DnD 3e was no suprise for me as I was lurking on sites like this long before I bought the core books

 

[pogre]

D&D 3E.

Millinnium's End - an old Charles Ryan game that has the coolest chargen and skills systen - plus an overlay system for shooting folks.