So many good choices; it's a great time to be a Knife Knut.
When it comes to "Best bang for the buck" questions I think implicit in that is punching above its weight. In that regard, there are some standouts.
Buck 110, as well as the Lite versions; KaBar's Dozier, Spyderco Tenacious, many Cold Steel knives - especially the AUS-8 Voyagers when they were on close-out; the 4-Max Scout is, as been said, a lot of knife for the money and though not a bargain basement knife, my favorite is the AD-10 as it hold its own in performance, fit/finish, materials and ergonomics with knives costing several times its price.
In fixed blades, again Buck knives are very knicely done and provide good value. I am also a fan of Becker Knives and all of Ethan's designs done by KaBar punch above their weight.
I will also say that while we all know what a buck (dollar) is we each define "bang" differently. Generally "bang" means value for money spent. That can mean many thing: looks, materials, warranty/customer service, pride of ownership; that's where things become complicated ... and fodder for friendly debate. That's why I can smile at the value received from my $35 (close-out) Cold Steel Large Voyager in AUS-8, my Sebenza as well as my AD-10.