Depends on what you like. For pure steel performance the Manix 2 Lightweight with S110V outclasses damn near anything else on the market, and not just in the $100 range. But if you want something with a bit more heft, the new H&K 14715 seems like a solid bet with D2 blade, G10 handles and the Axis lock. Then there's the Buck 830 if you dig flippers, great action and a really neat new lock. Or, if you love a good ti framelock, the Kizer 4403 is pretty dang nice. Maybe you like assisted open, talk to Kershawguy and grab a ZT 0566 for just a bit north of $100. Super-beefy folders your thing? Dendra Deer Hunter can be had for right around $109, shipped. No, more of a gentleman's folder kinda guy? Boker Plus Urban Trapper gives you a 3.5" VG-10 blade in a slim-and-trim package that weighs under 2oz. But maybe you don't dig knives made in China, so how about a super-classy Mcusta small Tsuchi?
There are a ton of great choices at or around the $100 price point right now. I don't think I've seen a bad suggestion on this thread, so I'd say check 'em out and see what speaks to you.