For learning ABC, 123:
Other than puzzles, and CD's you can get:
My little Leap Pad laptop. You can download his name, it plays music, teaches ABC and phonics. (Also get the fridge magnet with the little green puppy)
If you don't want to spend allot of money, and if you have the time, go to youtube and use this site http://keepvid.com/?url=chrome%3A//chromewebdata/ to download some of your child's most favorite songs, as well as other educational songs, burn a couple of dvd's and reserve them for TV time or quiet time. This way YOU are in control of what your kid watches.
Get him a leapfrog drum, that lights up and counts and sings ABC.
Leapfrog also has a set of maracas, one just makes noise while the other one plays music, names colors and counts to ten. You can set it to english or spanish. The colorful lights at the top keep them entertained while they learn motor skills while shaking the toy and at the same time learn to count, and learn colors. Also have a fun setting where you can shake it to make sounds as the music plays.
For Sensory Stimulation:
Sensory Balls (with spikes, or those that light up)
Rainmaker (A clear tube, with colorful plastic beads that swirls up and down the tube as you turn it over)
A trampoline - while he jumps, play a game with him while you watch the news.. say lets jump our abc
let him say abc as he jumps
play simon says as he jumps (simon says, touch your nose - and let him touch his nose, even if he can't say it yet, do the same with actions.. simon says.... sit down! Simon says... Clap your hands! Etc..) Teaches to follow direction, as well as body parts.
Balance beams.. you can make some from 2 x 4's or let him walk on your garden's brick borders. Teaches coordination and balance.
There are so much out there, and we spend so much money on stuff, where in the end, it is really the simple things that help us teach our kids.
Keep doing what you are doing, don't fret too much and go buy all the best toys in the market, you might find that he would rather play with the box it came in.
One thing I can tell you is to get a busy cube, maybe with an abacus on one side, and blocks on the other side where you can teach him the ABC's and animals.. Target has them and I think they are about $50 - yikes! Or look for something similar.