Kid: Laser Pico, mini fish, snark, optimist
Small adult (under 175): Sunfish, laser, holder 12, holder 14
Larger adult (over 175 and sometimes crew): Lido, capri 14.2, capri 165, precision 15
If you are a good swimmer these above are all pretty great boats to start with.
If you abhor getting wet, try a keel Lido, or a keel capri 14.2 or capri 165 (they are hard to find because sailing schools usually are the only ones who buy them).
I always thought a standard laser was a good single sailing, all around "learning boat." Easy to JUST sail... but also easy to learn sail controls (vang, cunningham, outhaul, mainsheet)...