If you have enjoyed the magic vs. tech setting in Arcanum I can recommend you some great stories written by Randall Garrett. His stories about the investigator Lord Darcy are set into an alternative 20th century where magic has replaced technology. The setting is of course different from the one in Arcanum, but in my opinion the Lord Darcy stories are a must for every fantasy fan.
You can get the paperpack version of the complilation Lord Darcy at amazon.com (or amazon.de for my german visitors).
Update: I forgot to link directly to the book in question… oops, my bad. It’s fixed now. 🙂