Personally, I like fondues that are little more than warm-ish ganaches that are a bit on the thin side. Use any chocolate you like to eat. If you won't eat it, don't use it for fondue.
I like to do a mix of dark and milk chocolates and use both butter and cream. Lately, I've been using a hot chocolate mix from La Siembra/Cacao Camino (Rodd Heino, a ChocolateLife member, works there) that has mild Mexican/Mayan spices in it. A little chile-pepper heat with some cinnamon, allspice, and nutmeg. The spices add some roundness and depth and complexity to the richness of the chocolate/butter/cream mixture and will complement most fruits or other foods you'll be dipping in the fondue. I use just enough to make the flavor present without calling attention to itself. I add the powdered mix to the cream to dissolve it completely. I start out with about 50gr to 1kg chocolate, how much I use depends on the kind(s) of chocolate I use.
I melt 1kg of chocolate in a double boiler until completely melted and then let cool to about 98-100F. I add the butter (1 stick, cut into pats) and mix with a balloon which until it is fully incorporated. The ganache will be very glossy. Then, also with the balloon whisk, incorporate warm (also about 98-100F) cream (how much cream depends on the fat content of the cream and the fat content in the chocolate - I just eyeball it). I'd start out with at least 200gr, making sure it is fully incorporated before checking the consistency. If it's too thick, add more cream in 50-100gr increments until it's where you want it. Keep the fondue/ganache warm to serve as it will thicken if you let it cool down.
I don't like most fondue pots because the gel heat source is usually too high and it usually scorches the bottom - well, at least for me it does. So, look for a small chafing dish with a water bath or use one of those small crock pots.
I know you said no oil, but I love to use a good olive oil (Lucini or Laudemio are favs) and infuse it with flavors of your choice (typically I use cocoa nibs and vanilla pod, cook for an hour at 80C, you can also use citrus peel, whole spices, etc) and I add to melted chocolate so everything is about 45C until the desired consistency is reached.