I'm as much of a bourbon snob as I am a beer snob, but I'm cheap, too, so here are some that are really, really good, in your general price range, and will be interesting alongside the Maker's Mark, Woodford Reserve, and Knob Creek others are likely to bring (good bourbons all of them, Knob Creek being one of my all-time favorites, though its big brother Baker's is my favorite from Beam).
Wild Turkey Russell's Reserve has a sizeable portion of rye in the grist, giving it a nice spicy, grassy flavor. Smooth, too. Bonus points because it was the first bourbon my wife liked, and it's hardly light on flavor.
W.L. Weller is a nice wheat bourbon, so will have a flavor that, to my palate, seems sweeter than the Wild Turkey. Another really nice whiskey at a good price.
Finally, Evan Williams Single Barrel is a fairly "typical" grist, but is simply a higher quality bourbon, a real sipping bottle. There's no better deal- other bourbons I'd compare to it go for 20 dollars more.
a +1 to the Elijah Craig 12yo- the bottle I keep on hand, as I can get it for about 20 bucks here. Buffalo Trace and Eagle Rare are fine ones, too.