I don't have any completely perfect knives. But I have a few out of my collection that I consider close to perfect for my needs.
1. Lone Wolf Harsey T2 Ranger, desert camo FRN handle - I love the ergonomics of the handle. It is grippy without being overly brutal on your clothing. It has great construction and excellent materials (FRN is not my favorite, but the texturing of the handle is well done). I absolutely love the blade shape - full flat grind with adequate belly and razor sharp out of the box. The only hit I will give this knife is the liner lock. I have had two liner locks fail on me (one of them was a Lone Wolf knife). I love this knife so much, I bought two others - a T2 Ranger with cocobolo handle, and a T2 tanto with black FRN handle. To me it would be perfect if it incorporated a frame lock rather than a liner lock. I can't believe Lone Wolf discontinued this series. I'm not really interested in any of their other models (I have handled quite a few). IMHO, they messed up the design by making the D2 Harsey a dual action automatic.
2. Zero Tolerance 0302 - This knife is just a brute of a folder. I love almost everything about it. It has taken everything I have thrown at it, and I'm sure it can take a lot more. The Ken Onion / Mick Strider collaboration is a perfect blending of the two species. The frame lock (my favorite) is a big plus in my book. Great materials. This knife should last several lifetimes. I also think the Zero Tolerance line of knives represent the best bargain in hard use folders. I have handled a few Striders. I like them, a lot. But bang for the buck goes to ZT. If I could only keep one knife out of my collection, it would probably be my ZT 0302 due to it being nearly indestructible.
3. Benchmade Dejavoo - Fairly large blade (almost 4"), light weight, love the blade shape, excellent construction and materials, super fast deployment. The handle is not only beautiful, but very functional and relatively ergonomic. I refer to this knife as being user friendly. It is easy to deploy, won't chew up your pockets, or cause a callus on your fingers. The only ding I will give this knife is what appears to be a relatively weak liner lock that doesn't seem to fully engage. Although, I have seen variability between different knives of this same model (some liner locks engage fully, others don't). However, I have not had the lock fail on me yet.
These three are in my EDC rotation, along with several others. The T2 and the Dejavoo seem to get the most carry time. I bring out the ZT when I know I will have more difficult cutting task.