Blue Jays are probably the largest of backyard birds. They are often seen in backyards across America but they are not frequent visitors to feeders. They mostly just come for the company, I guess. If you take away their reputation for being mean (maybe not warranted) and just look at them as they are, they are a beautiful bird too. Their large size, though, makes them look a little more ominous and awkward than, say, the delicate, smaller but similar shaped titmouse.
Apparently there is also a Jay called a Green Jay, though I have never seen one.