I'm partial to DaVinci sugarfree syrups.  You'd probably like the
Amaretto syrup, if you like almond flavoring.

You can often find various (wine-bottle-sized) DaVinci syrups in the
gourmet relish/syrup aisles at Marshalls, TJ Maxx, or Ross stores for
$5 or $6 a bottle.  Be sure to look for the blue-trimmed sugarfree
labels, because they have sugared and sugarfree lines.  

Unfortunately, the flavors found in those stores are just a random
few and you can't depend on a particular flavor, but you can get
the whole line, although a couple bucks more per bottle, from either
davincigourmet.com or from netrition.com  (netrition.com is a little
cheaper if you buy several bottles because DaVinci charges shipping by
weight, while netrition is a flat rate -- but I think DaVinci offers
a mixed-case price discount if you were to order 12 bottles)

For dessert coffee, I'm partial to the Irish Cream, Butter Rum,
Caramel, English Toffee, Vanilla and White Chocolate flavors,
and I've used at least half a dozen of the fruit flavors in shakes.
The only DaVinci flavor I was not happy with was the "French Vanilla,"
which I thought tasted pretty much identical to their pancake syrup,
without the thickeners.

I've tried a couple of Torani and Oscar SF syrups that I've found
here and there in supermarkets, but they both had sort of a shellac-
like aftertaste that the DaVinci syrups don't have.  I have to wonder
if only some people can taste that aftertaste, because a number of
people have claimed that Torani is as good as DaVinci.