Pretty pictures: Flowering Trees

I'm seeing tons of trees in bloom on the walks with Sheba lately, and some of them, in fact, have already peaked and have moved on to the next thing. So I figured if I were going to use the photos I've taken -- and I have way too much time invested in the photographing, selecting, cropping, and color adjusting of the pictures, at this point, to want to file them away just because they're no longer timely. So you're going to see them whether you like it or not.

I don't know what most of these are. Sometimes I'm pretty sure I have a genus, but that's about it. I'm not the tree guy. I don't have to care.

Tree number 1. I'm moderately sure this is an apple or crabapple (Malus sp.).
UPDATE: No solid consensus has emerged in the comments, but I'm more inclined to think Malus than the other suggestion, which was a plum (Prunus), as Malus would be the more common tree around here, and this more closely matches the fuzzy image in my head of what apple blossoms look like than any of the other flowers in this photo set.

Tree 1 again.

Tree number 2. The leaves coming in behind the flowers give it away as a maple of some kind. (Acer sp.)
UPDATE: Fairly definite consensus from the comments that this is a Norway maple, Acer platanoides.

Tree number 3. Pretty certain this is a Magnolia of some kind.
UPDATE: And people agree. Possibly Magnolia x soulangeana.

Close-up of a single flower from tree number 3.

Really really close to a single flower from tree number 3.

Tree number 4. I have no idea. Not even a guess.
UPDATE: Also thought to be Acer platanoides, though I would not have taken #2 and #4 to be the same species, so something about this ID is not setting well with me. This picture is somewhat earlier in the season than the photo for #2, so maybe this changes into that and they're the same tree.

Tree number 5. I'm pretty sure I ought to know this one, but I don't. Cherry (Prunus)? Crabapple?
UPDATE: Seems to be Prunus cerasifera (confusing common name: cherry plum, purple cherry plum), perhaps the cultivar 'Nigra.'

Tree number 5 again.

Tree number 6. No clue what it is, but the flowers are wicked cool.
UPDATE: Perhaps an ash (Fraxinus), maybe even specifically F. excelsior, though nobody sounds terribly confident.

Different angle on tree number 6.

Tree number 7. I don't have a guess on this one either.
UPDATE: Pretty definitely Boxelder (Acer negundo).

Tree number 8. I suspect a maple again, but I'm not sure.
UPDATE: Yep. Probably a maple. I'm thinking it might be another Acer platanoides, maybe 'Crimson Sentry' or some other dark red/purple cultivar. There appear to be a lot of those around town.

Tree number 9. Or maybe this is cherry. Or dogwood (Cornus). Crabapple? I don't know.
UPDATE: Probably a crabapple, Malus sp.

Close up on tree number 9.

Tree number 10, I'm pretty sure, is a redbud (Cercis sp.).
UPDATE: People agree; Cercis canadensis.
If anybody can help with my embarrassing case of tree blindness here, it'd be appreciated.

Thanks to everybody for their suggestions; if any commenters want to weigh in on the still-not-entirely-resolved cases of #1, #4, or #6, beg to differ strongly with any of the others, or just want to tell me the pictures are pretty, feel free.