The best bang for the buck bourbon with a little bit of searching, is Weller 12 year. Expanding on your point, lots of the best bourbons are actually a tad younger. Weller 12 year is the same juice aka distillate that is Pappy. Same exact stuff. Only difference is the part of the warehouses that the barrel is stored. The result is something that is strikingly similar if not almost the same as Pappy 12. It will be hard to find Weller 12 now, but after release in the fall it isn't that bad. Prices usually between 90$-150$ but it's spectacular for that price.
The Old Weller Antique 107 is about as good as it gets, seriously. It's the same mash bill at the Pappy and it's the exact proof as the Pappy 15 year......having had them both and likely for my wife far too often, they are strikingly similar. It can be hard to find, but I ran across a stash at a small town liquor by me in upstate NY and I was shocked they had it and shocked that they kept the price point where it was supposed to me. I've got two small bottles and a 1.75 in storage of this and I'm going to get more next weekend. I'm not as big a fan of the Weller Special Reserve (90 proof) it's a short finish on that, but I think it's a great bourbon for folks that aren't used to drinking a lot of bourbon, it won't knock you on your hind end with a huge finish.
I get the Old Weller Antique 107 very very inexpensively.
I'm actually now loving the 1792 Reserve, it's got a sweet finish that is really nice for me right now.
I will say that Heaven Hill isn't bad for what it is, seriously. People will scoff at a cheap bottle and never give it a chance, but it's a nice Julep bourbon.
The Buffalo Trace Antique Collection (BTAC) is great stuff if you can find it - William LaRue Weller, Handy Rye and the George T Stagg are all great and high proof (130 - 141 or so) which is right up my alley. I grab them whenever I find them, but they can be spendy. I've not had the Sazerac 18 or the Eagle Rare 17, because I've not been places at the right time.
I picked up two bottled of the Parker's Limited release of their wheat whiskey a few months back, but haven't tried them yet.
Sorry, could go on for hours on this topic.