We like Country Kitchen's 12-Grain Bread.
How this came about was, the kids had always eaten white bread--always. DH and I wanted to go healthier, so I bought the 12-grain for us. well, the kids tried it and liked it better than white, so now I have to just get the 12-grain. It's pricier, to be sure, but it's healthier, and fills you up better. I just thought it was so funny--we made no attempt to gradually wean the kids or anything, even the 4yo prefers the 12grain.
So, it might be easier than you think. I wouldn't call us a particularly healthy-eating family.
I use the 12-grain for everything, except if I make my own bread.