Well, thinking it was about time for a tree, I thought I would start with one of my favorites.  The Kentucky Coffee Tree (Gymnocladus dioica) is a hardy stout tree with few faults. 

KCT Leaf
Its biggest fault are its leaves.  A Double compound leaf means each leaf kind of has branches of its own.  They are also quite large from one to three feet long, they are almost like a palm frond.  Add the seed pods to the mix, a bit of a mess in fall and winter.  However, being so large they don't blow around so clean up is a breeze and due to the branch structure of the tree, there are not as many leaves as one would expect.

Notice the guy in blue to the left of the tree!
Mainly because of its leaves, the Coffee Tree has a spartan branch structure.  Typically 3-4 main branches and not much more secondary branching.  This is good for a couple reasons.  
Oklahoma weather is hard on trees, ice coating the branches, fifty mile per hour sustained wind speed, tornadoes, not to mention the heat and drought.  Having so few branches makes the tree very resistant to storm damage.  It has no "sails" to catch the wind and the branches it has are extra stout.
Also, the winter is friendly to the trees appearance.  Without all of the spindly outer twigs, the tree does not look so bare and makes for a striking and solid look.

KCT Seed Pod from http://donwiss.com/pictures/F-2000-03-19/
The Kentucky Coffee Tree received its name from the seed it bares.  Inside a large (4-9 inches) leathery brown seed pod are "nuts" that can be roasted and ground to make a coffee substitute.  But be careful, the seed are poisonous until roasted or boiled.  The seed hang on the tree all winter adding to its interest but later in the season they fall and can be problematic.

KCT Fall Color
This is truly a four season tree.  The leaves come out with a pinkinsh tint in Spring and fade to a dark blueish green in the Summer when is pyramidal form is really show off.  Fall comes with a mix of lime green and yellow, usually more of the lime green.  Finally in Winter, the contorted branches with a gray ruffled bark are put on show.  People will ask you how you trim your tree to keep it from looking weedy in winter.

This in one of the most versatile trees I know about, it will grow well in every state and into Canada and Mexico.  It thrives in moist rich soil but it also does well in the hot, dry, clay-pit that is central Oklahoma.  Roots are not a problem, it makes a great street tree provided enough over head room is given.  Regularly 70-80 feet tall and 50 feet wide with the potential for larger, they need room (but just a little!).  Stately Manor is a "dwarf" male(seedless) variety at only 50' tall by 20' wide.  
Water heavily the first couple years and you will have a extremely drought resistant specimen that will only require water in the driest of summers.  Pruning is unnecessary if planting location was wise.  Buy in winter so you know what your getting (male or female).  Both are needed to seed but close proximity is not necessary.  Pick one without any branches below seven feet or so; they are only going to get larger and you don't want to have to duck do you?