I understand your wife's fears, but I actually agree with you. Some time on TV or laptop is OK. I think that the most important aspects of such entertainment (tv, youtube, tablet, computer) is the quality of the experience you provide your kid with.
Here are the rules we follow for Electronic Entertainment (EE) with our 2yo daughter:
- all EE is moderated, we decide what can be watched/played
- no mindless staring - we watch tv with our kid and talk about what happens there, commentate on it sometimes, then, after we've watched it, we reference it in our plays
- EE is not a way to get something else done - it's meant to be just another way of spending time with our daughter (though we've actually violated this rule, we do try to stick to it)
- EE limited to max 1h per day and we try to keep 20-30 minutes per day on average
- some days are EE-less, when no tv is watched and no tablet games are played
I think that is is more important to teach a child that EE is not something bad, and it's ok to use it in moderate amounts, than forcing the though that it is bad and forbidding it, while the child obviously enjoys it. It'd be a huge contrast in child's mind and thus reduce your authority (i'm having trouble with words here, I'm not a native speaker). Most things are acceptable if they are used in moderation. The same, I think, works with EE. And if you don't teach your child early on to moderate the amounts, she may fall into EE even stronger later on. Consider this and talk with your wife about it.
As with all parenting, if you are consistent, your child will accept your actions regarding limitin EE time. No "one more please" beyond what you yourself decided should ever work. You can sometimes agree to it, but if you disagree, never change your mind.
I think that an hour per day for 18 month old is too much. Look at it like that: it's around 10% of her awake time. I would consider reducing the amount per day, and make sure to skip EE on some days altogether.
BTW: here's what 2yo our enjoys the most and we deemed appropriate for her age: Lego Duplo Forest/Circus apps on Android tablet and Bear in the Big Blue House on TV or Youtube.
2 years later follow up: our EE policy has worked reasonably well so far. Our daughter watches particular tv shows/songs and/or plays on tablet/phone reasonably frequently, but grudgingly accepts (=throws no tantrums) not playing/watching at all. We allow some tv time in the morning as we need that time for ourselves; she sometimes chooses not to watch tv as she prefers solo playing or coloring.