Well, first, a Buck 110 has a blade that's 3.75 inches if I recall correctly. The best 5-incher in my book is a Cold Steel Voyager. If you want a cutter and a knife for self defense, the serrated blade is the way to go. If you want it for standard cutting only, plus a secondary self defense knife, the plain edge is just fine.
Now you can go with the standard clip point or you can go with a tanto. Some people love the latter and others despise it. I like them just fine, though, so it's a matter of taste. Both are very attractive, effective designs. Blade steel is VG-1 on the newest knives and AUS8A on the older. If buying off eBay, make sure the steel is VG-1, as it's a tad bit better.
The knife on top is the Voyager 5-inch clip point; the one on the bottom is a 5-inch tanto serrated. I like both equally and have no preference of one over the other. You can also get the tanto with a plain edge or a clip point with a serrated edge. Again, for defense, the serrated blade is an excellent choice as it will bite harder than just about anything else on a blade. You do not want to have a serrated blade tear into you because the damage it can do is horrendous. It also cuts small twigs and branches, nautical rope and the serrations are so small that it will cut almost anything a plain edge will, plus it will stay sharp. The downside is, when you do need to sharpen it, it's a bit more difficult to sharpen the serrations.
Cold Steel also makes 6-inch monster blades. The Voyager X2 comes plain and serrated and the Vaquero Grande comes only with serrations. It's also available in a 5-inch. In the photo below, there are (top to bottom) the Spyderco Native 3-incher, Cold Steel Voyager 6-inch X2, Voyager 5-inch plain edge and Cold Steel 6-inch Vaquero Grande.
One last knife to consider is the Cold Steel Gunsite (below). It comes in 4- and 5-inch configurations and is one of my all-time favorite knives. It fits the hand like a glove and is beautiful. It's half plain and half serrated.
If you live where you can legally carry them, these knives are all astoundingly good. Cold Steel's blades come out of the box sharp and beautifully polished. I don't know any other 5-inch plus knives I can recommend. These also are very light.
Good luck with whatever you decide on!
The Gunsite comes in 4- or 5-inch blades. 
