Recommended Runs

Mud Baths: Runs that, with the right weather, get messy.
Argo and Bandemer Parks (one segment; see page for information), Bird Hills Nature Area, Bluffs Nature Area

Winter-Ready: Runs that are paved, sometimes plowed, utilized by other enough that the snow sometimes melts down.
Argo and Bandemer Parks (one problem area; see page for information), Border-to-Border Trail, Gallup Park (avoid Geddes Road)

Cardinal-Rule Proofed: The Cardinal Rule of Running, as I like to call it, is this: Don't Wait To Defecate. If anything's sure to agitate the remnants of last night's dinner, lunch, or pre-exercise granola bar, it's a run - no pun intended. These are the routes that have bathrooms - outhouses (which may only be open in spring and summer) and university buildings open to the public included. 
Argo and Bandemer Parks, Gallup Park, Nichols Arboretum, North Campus

Declivitous (and Some Precipitous) Nightmares: Runs with hills.
Argo and Bandemer Parks (only one section of hilliness), Bird Hills, Bluffs Nature Area, Nichols Arboretum

Conscious of Cleanliness: Runs that generally lack muddy areas, for those with new shoes, an attractive running partner, or no laundry money for a week. Note: no promises made for sweat stains.

Argo and Bandemer Parks (one problem area; see page for information), Barton Nature Reserve, Bluffs Nature Area, Border-to-Border Trail, Gallup Park, Matthaei Botanical Gardens*, Nichols Arboretum

Five Miles or Fewer
Argo and Bandemer Parks, Bluffs Nature Area, Furstenburg Park*, Gallup Park, Nichols Arboretum

Nichols Arboretum, www.flickr.com

Summer Saviors: Runs with water - often only dependable in the spring and summer months. (After that, there's something to be said for learning the ability to surreptitiously snag water from a hose spigot.) 
Argo and Bandemer Parks, Matthaei Botanical Gardens* (though the length might make having water at the end negligible), Nichols Arboretum, North Campus

Botonist-Friendly: Treed, planty, and flowery places.
Barton Nature Reserve, Bird Hills Nature Area, Bluffs Nature Area, Botanical Gardens, Furstenburg Park*, Matthaei Botanical Gardens*, Nichols Arboretum

Going Riverside

Argo and Bandemer Parks, Barton Nature Reserve, Border-to-Border Trail*, Furstenburg Park*, Gallup Park, Nichols Arboretum

Pioneering Routes: Runs that loop around enough that it becomes necessary to explore.

Barton Nature Reserve, Bird Hills Nature Area, Bluffs Nature Area, Nichols Arboretum

Night Runs: Runs that are relatively populated and have a smooth ground surface. Note: lights are NOT guarenteed.

Argo and Bandemer Park, Border-to-Border Trail*, Gallup Park

*See "Other Areas of Note."