Studies show that whatever approach you take will have a positive effect if you're *consistent* with it. However, of all the methods CIO is, overall, the most effective.
My approach with my own kids was to try non-cry methods (mamajama's idea of the routine; Naomi's gradual easing out of the room are both non-cry methods). If, by 9 months old they weren't sleeping 8+ hours, and going to sleep w/o a fuss, I used CIO. My first never cried; the second and third did.
With the daycare kids, it's a similar split: about 1/3 learn to sleep without tears; 2/3s end up crying. However, by 12 - 15/16 months, they are ALL having 90 minute - 3 hour naps, every afternoon, and with no resistance at all - in fact, usually with a smile and a cheery "nite-nite!". (This being Canada, they don't start with me until 12 months, which means that some come to me with good sleep habits already.)
CIO is extremely effective IF, as Diane says, you see it through. If, after 90 minutes, you go in and rock them to sleep, you are only training them to cry for 90 minutes.
Susan and Naomi are absolutely right: Kids who get overtired have MORE trouble falling asleep. We've all experienced the "second wind". You get tired, then, if you don't rest, you get past it and perk up. It happens to kids, too. Have a 2-year-old who never falls asleep before 11? Try putting him/her down to bed at 6:30 for a week. You will probably be astonished at how much easier it is.
Overtired = wired.
And your husband? He's not so far off. At 17 months, your child understands a lot more words than he can express. "This is sleep-time. This is not time to talk. Time to sleep," is completely within his comprehension. You underscore it by holding firm.
But I'm curious: If you hold his hand and he goes "right to sleep", is there any need to change the pattern? Are you holding his hand for two or three minutes? Or twenty minutes? If it's the latter, it's maybe a problem. If it's just a couple of minutes, does that really need to be changed? If you're concerned that two minutes might end up becoming 20 minutes and then 2 hours, you might try holding his hand until he's almost, but not quite, asleep, and then leaving.
But really? If it's just a minute or two and shows no signs of turning into a prolonged song-and-dance, I don't see that you need to change it. It sounds quite sweet and harmless.