Hmmm, tough call.
Toto? very talented band and great songwriters but in my opinion they never really put out tremendously awesome albums, just great songs here and there.
Boston? love em but with one album every 8 years I'd be hard pressed to give them the title.
Foreigner? Probably had the most hits of the 4 bands. Thier 70's stuff rocks pretty much, and in the 80's they were huge.
Journey? The best of the 4. Alot of hard rockers hate the sappy ballads but they started out a jam band and were very talented from the beginning and made the transition to arena rock and 80's MTV rock quite seamlessly.They produced great records start to finish for 10+ years until Raised On Radio.