Doomsday Book by Connie Willis is a good one for time-travel. Actually, To Say Nothing of the Dog also by Connie Willis is a good time-travel novel too.
Almost anything by Neil Gaiman is great. Fantasy, but fantasy based closely on modern reality.
I am also reminded of Chuck Palahniuk(sp?), author of ‘Fight Club’ (gangs?). All of his books are great, but one in particular, ‘Lullaby’, is a funny take on Super Powers/Magic.
If you’re a fan of Douglas Adams - “Dirk Gently’s Holistic Detective Agency” has some time travel within it…
The characters act as normally and logically as you could expect Douglas Adam’s characters to act - - also it is a comedy…
in fact “Life, The Universe and Everything” from the Hitch-hikers “trilogy” also has some nice time travel discussion - - about paradoxes etc…
probably not what your looking for - but still… you might like them
Lyndon Hardy’s Master of the Five Magics has a logical and organized approach to magic and has demons there also may have been prison. But no time travel or street gangs.
Brian
Robert Heinlein’s Job: A Comedy of Justice takes you through Heaven and Hell.
Larry Niven is better at science fiction than fantasy, but he wrote some stories about magic:
*Not Long Before the End * (short story)
*What Good Is a Glass Dagger? * (short story)
The Magic Goes Away (novel)
Niven also wrote a series of short stories about time travel, collected as The Flight of the Horse. It has an oddball twist on time travel.
How come no one’s mentioned the best time-travel novel I’ve ever read, The Man Who Folded Himself?
For time travel, you might check out To Say Nothing of the Dog by Connie Willis, in which a 21st century historian travels back in time to Victorian England.
I know you said novels, but if you haven’t seen it, the movie Time Bandits has pretty much everything you listed.