In Illinois, you likely have ruby-throated hummingbirds, although your description doesn't exactly tally with them. But they're by far the most common hummingbird in the east. Females have greyish white throats with iridescent green backs and tail feather, and males are similar except with the namesake ruby throat band that can also appear black or orange depending upon how the light hits it. There are variations from bird to bird, and eventually you can even identify your regulars by nuances of color markings or even head shape. Check out the links below to see if these hummers look like yours.

Well, now that I snapped a few pics I see that the color changes in differennt light and at different distances.
So I guess this must be a Ruby Red Throat?

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We posted at the exact same minute!...yes, you have ruby throats. Even though we're not as lucky in our species diversity as those in the west, ruby throats are wonderful birds and we have them in profusion here. Keep those feeders fresh and enjoy the show!

By the way, great first pics.

Took some better shots today, however he gave me some dirty looks, made some strange gestures and I haven't seen him the rest of the day.

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Ha ha! Great stuff! Definitely dirty looks.

Lots of hummer attitude! :0) Great pics, thanks for posting them!!!