Vanilla is such a good base note; I'm trying to think of something it won't go with. I frequently use it as my "fixer" to even out scents I don't like - super sweet, very heavy florals like jasmine; things that are too fruity.
All of the above and in addition I like it with lemon verbena. I love vanilla (but not the buttery, bakery vanilla) and I believe it really goes with everything.
I blend it with clove and cinnamon. I use the clove fo from WSP so I can go a little higher in percentage in the blend then if I use the eo, but I'll mix in a little cinnamon eo too for a nice blend.