I have 3 children, 2 in college and one in daycare, and another on the way. I followed attachment parenting with all my kids and the only wanting to be held all the time, runs its course. My children actually were very happy and content because they felt attended to. Even in daycare, my children enjoyed stimulation from having playmates, even at a very young age. My sister let her kids cry it out. Which drove me nuts. But it worked for her. Do what you think is right. There was is no wrong way.
My daughter is 21 months and has always been a hold me baby. She wouldn't even sleep in her crib, so she sleeps next to me. My mother in law watches her when I'm at work so she gets one on one attention there. But in your situation, from what I've read, your son will probably need you to hold him after his day at daycare to help him feel, I don't know the right term, calm and connected? I really like the Dr. Sears website. They have a ton of questions and answers on topics like this. Check it out, you may find some good ideas to try out and see what will work best for your circumstances.
I would go with attachment for at least the first few months to 6 months. Babies need to feel safe and they can only comminicate by crying. You wont spoil them when they are still tiny, just when they get a little older. Check our Dr Harvey Karp, he explains how new borns are in a 4th trimester and what needs they have. He also shiws a swaddle technique that works like no other :)
Depends on the child really.