Rather than logging my steam account into a third party site I simply pulled my purchase history from Steam and I've spent $232.47. Through I should probably check Humblebundle for a more complete figure.
My most expensive purchase, the only thing not on sale when I picked it up, as WH40k Dawn of War with all of the DLC which clocked in at $38 bucks. Skyrim, and all of it's DLC, only ran me $26 so that seems super expensive.