Well rather than try and review them one-by-one I thought I'd try and cover off the series to date (I'm up to Book 5) because in may ways they all blur into one, or at least have such a commonality of strengths and flaws I'd quickly get tired of repeating myself. This isn't, I hasten to add, necessarily a bad thing, as familiarity can be reassuring and allow a writer to work in wider themes, and shock you out of that familiarity a little more easily. As of Book 5 I've not seen a lot of sign of that, but maybe thats in the future.
So The Dresden Files - which oddly aren't written as case-file style memoirs despite that being a potentially great device for them - are set following Harry Dresden, Chicago's only Wizard who appears in the phone book as such. He's also a Detective, although probably a pretty terrible one as he never seems to make and money and I've not seen too much Detecting out of him. Harry's world is just like ours, with the addition of every supernatural entity ever, often lining up to ensare him in their schemes or just give him a good kicking. Harry, on the other hand, is a pretty powerful Wizard, which makes him the perfect underdog hero, the sort that spends a lot of the books getting turned over, but one whom you know is really capable of pulling something out of the hat.
The is best summed up in The One With All The Werewolves (also a great Friends episode they never got around to making) where you have three distinct types of the damn things ranging from pretty friendly shapeshifters to full-blown unstoppable killing machines. Vampires are treated the same way, and I imagine as I read forward it'll end up like a veritable sticker-album of different versions of different supernatural entities. The way the books juggle this is pretty cool, everything exists, but they exist in a complex balance of rivalries, alliances and just sort of vague co-existence, and Harry collects allies as the series goes on, even if they do seem to conveniently vanish on occasion so they don't get in the way of the current storyline.
The other great skill of the series is managing to feel breezy and fun whilst dark and horrific without the two impulses ever getting in the way of each other. People die, or have other horrid things happen to them, and as mentioned Harry himself seems to spend at least 3/4 of any book being beaten up some manner of supernatural gribbly or other. But they also rattle along, without ever getting to bogged down in all that darkness, As a reader, its a bit like being a tourist, a horror ride without any real threat or unpleasantness that lingers.
In the final analysis I becoming rather fond of the The Dresden Files; they're fun and accessible and quick to read. Thankfully there are loads of them still to get through, and maybe, just maybe, he'll pull off a shock yet.