I *am* into p&p RPGs. I started gamemastering about 5 years ago. I have run campaigns with different roleplaying systems, and I can give you my *personal* opinion about them, if you'd like to read it.
I have gamemastered D&D, the Call of Cthulhu, Fudge, RyF and g&g (this last two are free Spanish systems). Although I started with D&D, it is the system I like the least by much, for the reasons I will state now:
First of all, the class and level based systems, under my experience, hinder roleplaying a lot. Roleplaying is about getting involved in your character, not about contemplating statistics, gaining experience points and rolling dice and stating "I kill the orc" every 10 turns. In D&D I find moral constraints put on my character (alignment), not letting me enter into the depths of the reasoning behind him, because the alignment is pretty much forcing it two-dimensional. The class system hinders freedom of doing the exact character I like. I mean, why can't I roleplay a bartender, or a merchant? and what about a Elite Guardsmen of the King, specialized in swordfighting and cooking (for example)?. Stating "I am a Lawful Good Paladin", even to yourself (as that phrase is *strongly* out of character) is just putting you into a very determined place, and kind of forces you to play your character on some way. Why can't I be a cynic, sarcastic, cruel holy warrior? And then we have levels. You suddenly wake up one day and you know a) several spells more b) how to fight better c) a new fighting maneuver... It just does not make sense to me.
Then there is the money issue. D&D is very expensive, in my opinion. 3 books at 35€ per book is kind of expensive, but if you plan on staying updated, be ready to give away more money.
And let's not forget about thousands of rules and spells which, as a gamemaster, you must "memorize" in order to create adventures "by the rules".
So, what do I recommend? Something that gives freedom to both the master and the players. I prefer a simple system, where I, as a master, can go on and make up a rule for every situation without worrying about rulesets or spell descriptions. I prefer a system where I, as a player, are not restricted by arbitrary definitions like level, class or alignment, and where special combat maneuvers do not require a "feat" but just some common sense from the master.
I have not personally player GURPS, but I guess it could do the trick. I do recommend, though, Fudge, which is kind of special but a very nice system nonetheless, and freely available on the net:
http://www.fudgerpg.com/I would also recommend Rápido y Fácil (Quick and Easy), or RyF, project available under the CC-by-SA v2.5 license, it is freely available and you are free to do derivatives if you publish them under the same license. I have been involved with the creation of some rules and one "theme" for this system (Año Cero, or Zero Year, which is currently on hiatus due to excessive work at university
). It is available in Spanish here:
http://mercurio.homeip.net/ryfYou can speak with the main author so he presses onwards with the translation into English, though
. Right now there are only a set of outdated rules from the former "Present day" theme:
http://mercurio.homeip.net/ryf/index.php/RyF_Actual_BasicAlthough the main system is theme-less, and so useable on *every* situation you can think of. If you have more questions about this system, I can answer them without problems, so feel free to ask away
Since I switched to RyF, I do not play any other system. I liked it so much I became a little involved with the project, as I stated earlier.
Just so it is clear: this post was *my* opinion on RPGs
If you prefer D&D, then by all means play what makes you happier
EDIT: Links. Also, the author said that probably a corrected English translation will be up. I'll be sure to keep you updated.