As a kid I loved toys and when I got my own baby I was excited to start buying him some toys as well.
So I can play with them. So he can learn and explore through shapes and colors. We acquired a couple infant toys and put them to the test. I was excited to see how my boy would interact with his new treasures. Turns out that babies could care less about toys! He was (and still is) more interested in my hands, fingers, ears, etc.
When he got to the year stage - kid toys started to pile up. Different trucks, stackers, shapers, stuffed animals, etc. He would play with them for a day and then lose his interest completely. He likes to play with car keys, wallets, remote controls, cell phones - pretty much anything that's not a toy.
I say until your kid is ready to ask for toys himself, don't clutter your house with things no one will play with. Don't deprive your child completely, but 2-3 toys is more than enough. You can rotate them by putting one away and taking it out after a month. Kids have short term memory and to them it will be a brand new thing to play with.
The best kid toy I can recommend is Lego Duplo or Megablocks. My kid seems to love building towers. Thus I can swear that he's actually learned something from it.