How many people are in your family? If there's 4 or less, you could stay in one of the value resorts. We have stayed in WDW resorts in all categories, and our stay in All Star Sports was one of the most fun trips we had. Since this is your 1st visit, you won't be spending that much time in your room anyway. There's something more magical about staying onsite, and it seems like you're able to get more done. We have stayed offsite, and IMHO staying offsite in a condo is perfect for a more laid back trip, but who wants to be laid back on their 1st trip?

The regular hotel rooms offsite, aren't that much cheaper than onsite, unless you're comfortable staying anywhere. For example, we have a pet, so we either have to stay in our RV or offsite. I've been searching for a decent, clean place to stay next month, and I haven't been able to find anything that won't cost us
more than a value result on property would. Have a great trip!
I guess I was typing this at the same time you all were, but it should still apply.
I forgot to mention, that if you stay onsite, you won't have to rent a car, which will save you money also. Everyone doesn't agree, but we enjoy taking WDW transportation. We think it's more relaxing than driving, and adds to the overall experience.