I really like Questers of the Middle Realms or The Zorcerer of Zo for low GM prep work.  Both are based on the (free) PDQ core system.

ZOZ also walks you through an example of a short campaign, from 3-line pitch through episode-by-episode prep to conclusion.  ZOZ is centered on fairytales, but can be used for swashbuckling or high epic, or Star Wars if you want.  QotMR is more classic fantasy, very close to a D&D setup, and offers a little bit more structure (though still light-handed).  

In both cases, I like the fact that it's very easy to come up with NPCs on the fly if you need to, and that PCs kick ass right from the beginning.  You can prepare for a game by jotting down ideas, sketching a few characters and places, but you don't need pages and pages of notes in advance.  It's easy to wing the new stuff in play.

My own on-going supers campaign is also using a system based on PDQ, Truth & Justice, that benefits from the same advantages.  It has made my life much easier, as GM, than other systems I've run (including AD&D, Harnmaster, oWoD Mage, Silver Age Sentinels, M&M 2e, and many more.)

Quote from: AkrasiaIf you have a copy of the old Moldvay Basic Set (or Mentzer Basic Set), I'd go with that for a few sessions.

Or the Holmes basic set. All of these are great option, really. You may also want to look at the C&C "Collector's Edition" (basically a simplified box set homage to the aforementioned Basic Sets). The latter is in overstock at Noble Knight Games. You can pick up a copy for $30, plus shipping (IIRC).

Provided your players know you're a first-time GM, I would go with a core-only D&D 3.5.  The veterans will be there to help out the newbies and may even help you out (without being all rules-lawyerly, hopefully) during your game.

I would also suggest a first level adventure.  Either:

Scourge of the Howling Horde -- It is the first WotC adventure in the "Delve" format; basically a laid out plan of attack for each and every combat encounter in the game.  It does help new GM's quite a bit, but the adventure itself is very plain and basic.

Idylls of the Rat King by Goodman Games is the original "Dungeon Crawl Classics" adventure.  DCC's are a wonderful resource and most of their adventures are at least pretty well done.  Any of their 1st-level adventures will do, but this is generally regarded as one of the best.

If, for some reason, you decide to go easy on the players ("the first hit's free" and all that), run them through Legends are Made, not Born.  Its meant for 0-level characters (the NPC character classes: Warriors, Experts, Commoners, etc) but you can substitute your standard 1st-level characters with no problem.

Now since you like to make your own campaign worlds and adventures and such, the big benefit to having one or more of these adventures is that you now have a bundle of created -- and creative -- monsters, NPCs, traps, maps, towns and all that, to mine at your leisure.

Good luck and have fun!

Go with D&D.

You're familar with it (most important for the guy running the game). The new group will be too.

Quote from: enelsonDo not run a game you do not enjoy. If you are only running fantasy because your players like fantasy but you do not, then you will not have any fun. It is important that you have fun as the DM.

oh no, I like fantasy too, because I've found it's easy to integrate lots of different styles (I have a choose your own adventure thing online which has cute talking animals and unicorns, but also Lovecraft-style evil gods etc)

Quote from: enelsonJust some thoughts to consider:
Since your group is new, do not be afraid to layout the boundaries of the game. My friend tells his players ahead of time what are the boundaries so everyone is on the same page when they create characters and play the game.

This sounds like a good idea. I was thinking of saying that, until I have enough material to run a campaign where you can wander at will, you have to make characters that are going to want to go on and stay on the adventure ie they have to be either heroic, or have some other motivation like being obsessed with being famous heroes, or absolutely need the reward etc. Also people need to coordinate their characters so that there are no crippling conflicts.

Quote from: RoninWell if you like the looks of Simple, and Perfect 20. You might take a look a True 20. I know theres a lot of people here (or sometime it seems like anyway) that like it around here. I have the agree with Sosthenes I like the Conan D20 variation. If you want to play something other than D&D but keep that old school feel so to speak. You may try Tunnels and Trolls, or Castles and Crusades. I'm not very familair with either. But I know a lot of folks around here are.

Tunnels and Trolls would be good, because I'm pretty familiar with the rules from playing the gamebooks - and there's only really two mechanics that it uses, saving rolls and rolls for combat.

What I don't like about the rules is that you can't be anything other than a warrior or a wizard (or a combination of the two).

Has anyone ever done an expansion for it with different types of characters?

I forgot to suggest that picking up one or two sets of WotC's Dungeon Tiles can be pretty handy too!  A few months ago on my first foray back into GM'ing I suffered from a complete brainfreeze and simply couldn't remember what I wanted and was going to do.  Thankfully the crew was already at the entrance of the dungeon so as calmly as I could muster I randomly laid down some tiles, paged the Monster Manual for some CR2 and lower critters and went at it.  Eventually I regained my bearings and got the adventure back on track.

There's four different sets of the Tiles, three of them are dungeon related.  But if you're not the dungeon crawling type the fourth one is outdoors and wilderness related.