Given those two choices, RC. I'm not a big fan of some ot the optional rules like skills and weapon mastery and I don't like the focus on the super-high levels, but as a whole I like it much better than 2e.
Rules Cyclopedia. There's something magical about a one-book self-contained rules set.
While I don't really hate 2nd Edition (I always preferred 1st Edition), one thing that bugged me -- and that now bugs me about 3rd Edition -- was the glut of material available. When there are so many rules out there, the focus shifts away from story/plot/campaign to powering up characters and collecting every little rule/book you can.
The Rules Cyclopedia (one of the treasures in my RPG collection) will allow you to better focus on the plot of the story.
Without any question, go with Rules Cyclopedia D&D. Much, much better than AD&D2e, which is the game that drove me away from rpgs for several years. RC has the spark of wonder and simplicity in it that I used to love that 2e drove into the ground and spit on it's grave.