Which game that you've played has the best/most realistic system for attributes, combat, etc? I was trying to modify SR, and dicided to start from scratch. Thanks in advance for your help.

HERO System, 5th Edition

Well the best, realistic system I have seen is Phoenix command. This is a game designed by former Vietnam veterans, it is one of the few systems I have seen that you can get shot in the leg and bleed to death in minutes.
The next system is The Morrow Project, where all firearms damage is broken down into the number of inches of wood it will penetrate and converts that to the damage your body will take with intense bleeding and chances of death.
Both of these systems are complicated, but very detailed.
Changing to a different system might however alter the flavor of the shadowrun universe.
My groups answer was to use hit locations, with specific armor and damage charts for the different parts of the body.(Head, arms, torso, and legs.) We have also switched to d10's instead of d6's, now even pedestrians can drive without having catastrophic wrecks 2-3 times a year.
Twilight 2000 is a pretty good system, and its successor traveler 2300 was simpler without loosing anything.
None of these systems utilize magic, though the Phoenix command supplements may have some.
Now chaosium has a modern Cthulu setting that does have magic, and monsters, and the combat tends to be quick and deadly.
Parabellum

Depends on what you want:

"Military Action", "Action SciFi":

Traveller:New Era (Expanded Twilight:2000 Version 2.2)
2300AD
Milleniums End (If the GM knows the system by heart)


Cyberpunk, Animee, Action-Superheros:

RTal Cyberpunk 2.0.2.0
RTal Fuzion (Bubblegum, Champions)


General Gaming (Fantasy, Char based SciFi, NearFuture, Now):

GURPS 3.Ed (But beware of the MinMaxer and CanAll)


Horror

Call of Chutulhu (With a goooood GM)


Star Trek

Last Unicorn Games[1]


Fantasy

Harnmaster (For character based stuff)


Systems I do not! recommend (The settings may be a different thing)

Renegade Legion/Legionaire (I like! the setting)
Rolemaster/Spacemaster/Cyberspace (including the settings)
(A)D&D
DSA (exspecially the setting)
Shadowrun


Systems I play/master when it fits the genre

Star Wars

West End Games D6


Traveller:

Megatraveller (I dislike the older rules and hate the TNE setting[2][3])

RIFTS

Mechwarrior 3rd Ed.


Michael


[1]Judging from Lord of the Rings the Decipher-Version might be even better
[2]But use the system for most action-based stuff
[3]Gurps:Traveller is among the few Gurps Books I hate. That <deity>damned emperor is still alive - I hate it.

Whatever you do, do NOT use Fringeworthy. It may have rules for calculating wind shear on individual shotgun pellets, but the holes in the system are big enough to drive a Great Dragon through.

~J

Well, other things like Terrible conditions or other unusual circumstances can force a test, but in general you're right, these things shouldn't be causing tests. It's like saying that every once in a while someone will rule-of-1 their Strength test to open the bathroom door and have an "accident". Some things don't require tests.

~J

Rolemaster is a really good system for realism. You would need Weapon Law: Firearms, as well as all of the magical school books (Elemental, Arcane, etc.) to get close to rounding out all of the magic and gun rules. Great system for making a low-fantasy character. Slow experience progression however and you'd have to be okay with level & class-based characters.

If you ask me, just use the existing rules and tweak it as you like it. SR is truly a unique game. Major kudos for not buckling under the d20 goblinization.

I have to admit, the Rolemaster Critical tables were always a lot of fun.

-Siege

Everybody knows the F.A.T.A.L. system is the best RPG ever right? It says so right on their site, it's the most accurate system ever made!

Since I'm too drunk to operate Google properly, what's the website?

-Siege

Cyberpunk 2020 as accurate?
What?!

I mean, I love CP 2020. Adore it. But no matter what you do or how good you are at it, one out of every ten 'uses' of the skill, you'll end up shooting yourself in the face, breaking what you're fixing, or otherwise horribly screwing up.

So I would have shot myself in the face hundreds of times already? And I still look good.

Im referring to making stupid mistakes even when you think you're really good at something.

Not 10% of the damn time!

Unknown Armies works on a percentile system, and it's an absolute work of art. It's beautiful and I want to bear it's children.

Yep. Every skill check is based off of a 1d10 roll, adding your stat and skill to the number.

You roll a one, you fumble.

...but wouldn't that almost be the d20 system with a smaller die?

And I thought d20's 5% critical failure system was full of shit...

It still is.

GURPS is good. It has its flaws, especially when you start moving to creatures noticeably bigger or smaller than humans, but the bottom line is more on the positive than in just about any other game I've seen.

And the thing can be adapted to most anything, though in practice the number-crunching and tweaking involved isn't worth it.

Rolemaster, or Rulemaster as I like to call it, is just bad. It has about all the faults of the *old* AD&D (like ramrod-stiff class divisions and a really stupid armor system) without any of the good points, such as easy playability. And the combat rules are just awful; a char of mine once tried to restrain another by grappling, and thanks to rolling an open-ended almost ended up killing the guy... Doesn't sound like something a trained martial artist would do, IMO.

And neither Arethusa nor Crimson Jack know what d20's critical failure system is so they're full of shit, too...