Having played AD&D, D&D 3E, Warhammer, L5R, Deadlands (Classic), and maybe some more, I think a great yet quite simple system is Deadlands one.
- Skills based on general abilities (Perception, Strength, Spirit, Knowledge and so on) with sub skills you can buy with experience earned (like guts, medicine, shoot: rifle, fight: knife, quick draw, etc.)
- Simple damage system with definitive damages,
- Advantages and Hindrances (mandatory to obtain characters with souls, not like in D&D ^^).
You should take a look at it, it's not a perfect system but at least an very enjoyable one.
Some doc for inspiration :
http://www.ehow.com/how_2310518_create-character-deadlands-classic-role.html
http://www.scribd.com/doc/2499571/Deadlands-Character-Sheet-1

Action point turn-based system.
So a bit like the old Laser Squad system, but fully text based instead of with a GUI?

So instead of Simple you should call your system Normal...
... or rather call it Easy. ;)
I think you'll never ever need "sub-skills", no game needs that, even when it does. Get the Fallout skill list at worst, drop the duplicates (doctor x first aid, speech x barter, small/big guns x energy weapons), or even better, do like Deus Ex and only use skills you'll use in the game mechanics (different weapon types, computer, swim, lock picks etc).
I'm all for it, but note that most people hate that formula even when they like Fallout.

I can't see the link for some reason.
Perhaps I will send some ideas later. Are you planning for some serious sounding perk names or more humorous ones?
BTW I would love to see some popular culture jokes in the game. Red Dwarf comes to mind... (Space Corps Directive #349
Any officer found to have been slaughtered and replaced by a
shape-changing chameleonic life form shall forfeit all pension rights.)

I was really thinking a LOT about sub-skills and I think it would really give player a chance to aim for a certain character, which would, in turn, suck one in the game even more. However, if it won't work, I'll just drop it of course :D
True, but what better system could I have for text-based RPG, really?
Rapidshare link
Of course, personally I WILL write culture references, because I just do that when I write sotries :-) But I can't say it for other writer that joined me.
And I'm talking about serious perks bound with skills from the text file

Oh, of course, 'cause... That would be boring :D

Okay, I managed to download the document (I have no idea why I didn't see the link before. Most likely my own mistake.) and will send some ideas tomorrow.
Sorry for the stupid questions. I also seem to have somehow been able to quote my whole last post. :/

I've always been a fan of the D&D rules. Never played the Pen n Paper though. But Baldur's Gate has kept me hooked for many many years. I also rather enjoy the whole Elder Scrolls way of life. Morrowind anyhow is what comes to mind where you have a base set of skills and you are defined by whatever you train most in during your adventure. Would a combination of the two be possible? Regardless, can't go wrong with D&D rule sets, maybe come up with your own specialized classes and skills? FATE, in my opinion, also has a great system. Don't leave out the AGE aspect. Maybe can't get into certain areas if your character is too old or too young? Age affecting your combat abilities, wisdom and intelligence? I believe DarkStone made your stats decrease when you reached a certain age and older, forcing you to find potions of youth. Just a few ideas. Good luck with it!!

I love DnD, but DnD (even BG) is, quite frankly, ridiculously complex. Not to be rude, but if you think DnD is remotely feasible for a first time dev, I don't think you understand the amount of math and stats behind it.
Honestly, I think first time devs just shouldn't touch RPGs unless they have a heavyweight statistics background or have worked with PnPs. If the OP is still serious about this he/she should look at MUDs code and read some PnP books (GURPS might be a good reference point as I believe someone else mentioned), not look at a DnD videogame.
Keep it simple.

DnD? That would require me to read a pretty long book just on the rules again :D

Oh my, I hate randomness in character-building (which always yields unbalanced starting characters with different power levels), but you gotta love a western-themed game that has playing cards in character creation! :)

I find this skill list overly long, but then again this is the kind of thing you'll have to adjust along the way in any case. Example, I never saw a videogame where you had skill "chemistry". If you end up making some game mechanics using chemistry, it could be great; if it turns out useless, you'll know and you can drop it later.

IIRC Arcanum has chemistry skill, doesn't it?

It's a riveting read, I'm told. If you don't like reading, GURPS is great because you can pretty much fuck it up however you wish.