Are there any decent fantasy books in a modern setting where magic and technology not only coexist, but actually enhance each other? Or even where magic is just used as a part of mundane, normalized society? Like wizard Starbucks baristas, or accountants, or whatever?
The Night Watch series is kind of like that, but I think it’s more that magical items are disguised as mundane things like flashlights and cellphones so as to not attract attention. Either way, magical flashlights are clearly enhanced over their ordinary counterparts.
Charlie Stross’ “Laundry” series has both magic and technology, with technological magic being much more effective than pre-tech magic.
There are lots of books with magic as a mundane part of society:
Harry Turtledove’s “The Case of the Toxic Spell Dump”
Heinlein’s “Magic, Inc.”
Randall Garrett’s Lord Darcy stories
Poul Anderson’s “Operation Chaos” and “Operation Luna”
Infovore’s series doesn’t quite meet either of the conditions in the OP, but magic and technology do coexist (most people don’t know magic can actually work). The main character is a college professor with a scientific approach to magic, and both him and other characters make use of “normal stuff” as well as the magic bits.
I promise he eventually stops killing every character that has more than one line of dialogue :p. Well, OK: he only seems to have done that in the first book. Bloodthirsty writers…
The Shadowrun games and books are all set in a universe in which magic and tech coexist; they’re antagonic in some respects, complementary in others.
Blish’s *Black Easter *posits a modern world where magic exists. The monks have computers and use them when it is easier to do than performing magic.
Rick Cook’s Wiz Books series has a computer programmer who designs a way to compile magic spells much like using a computer.
And of course, Harry Dresden uses magic and technology, although he does have issues with it. 
The series Incarnations of Immortality by Piers Anthony is set in a world like 20th Century Earth but things run on Magic not science.
The game Arcanum is Fantasy crossed with Steampunk.
You might try the Rivers of London series which peripherally explores the interaction between the two. And the protagonist is a user of modern technology.
Diane Duane’s “Young Wizards” books are generally pro-technology, and in fact show wizardry as similar to a kind of highly advanced science. There are many examples of wizadly computers and other digital devices.
The Rivers of London series by Ben AAronovitch fits the bill.
Set in modern London, magic is real but known to few. It fries electronics when cast so the hero, a London cop, has to switch off mobiles, use analog watches etc. when casting a spell. Also magic use causes long-term neurological damage.
Rachel A. Marks’ Dark cycle (starts with Darkness Brutal) is urban fantasy. Look at those books, and Amazon will recommend LOTS more. Urban fantasy has been big lately.
Magic 2.0 series by Scott Meyer.
A bunch of computer geeks discover that the world is a simulation and you can access and alter the main code. They travel back in time to medieval England and establish themselves as wizards.
Mercedes Lackey has several series of books which mix magic and technology in the modern world. On her web page, I see she lists them as being in the Elves on the Road Universe:
Bedlam Bard: Ren Faire flautist finds that magic works for him if he’s playing
Diana Tregarde: Paranormal investigator and sorceress
The SERRAted Edge: Elves and motorcycles.
Harry Potter>
The urban fantasy and paranormal romance genres have fantasy coexisting in our current society, though It’s kept secret from the mundanes.
Christopher Moore does this all the time.
A lot of mentions of good reads listed already.
My neice used to have part of a series about the romance, politics and infighting of modern day elves and their interactions with modern day humans, wish I could remember the name, parts of the stories could be rather racy.
The Castle series by John DeChancie iirc has magic and technology co-existing if not integrated.
Simon Hawke’s Wizard of 4th Street series was about such a society. Basically, society collapsed when the fossil fuels ran out, then magic came back and society rebuilt itself with the new power source, integrating it with technology. So you have half magic/half technology flying cars, power plants run by wizards and the like.
the books based on the shadowrun pnp game is what your looking for its a unique mix of old world magic (merlin based magic) new world magic (American indian shamic/totem) and technology gone amok
Tho the books seem to he hard to find … I think they made a series of 80 or so and some are better than others they start out about 2050 and end about 2080 or 90…
only problem I have with her is unless she changed her motif is most of her stories are about abused/exploited in some way children even if they aren’t the main characters …
Aww, thanks for the plug! And to address your spoiler…
Yeah, it’s not a good idea to get too attached to the non-main characters, but I don’t kill them all off. 
That’s what I actually came in here to mention. In Shadowrun, it’s entirely possible for mages to also be deckers (computer hackers) or even to split their focus between magic and cybernetic implants. Most people are at least passingly familiar with/comfortable with technology.