I'm looking to stab someone. What weapon should I pick?

The weapons, shiv, screwdriver and scalpel are all of the stabbing category and all take the same weapon slot (you can only have one of them at any given time).

What are the differences between them? Which is the best stabbing weapon?

Solution 1:

There's a weapons FAQ that covers the differences between shivs. The listings give identical speed/strength ratings to all shivs, but notes differences in the description anyway. I couldn't tell whether those differences are real or perceived, since they're not explained well, but here they are anyway (bold is my emphasis):

Carved Bone

• This looks like a bone, that was carved into a Shiv. It looks pretty cool, and it can only be got at one point in the game: When you kill Alonzo.

Shiv (Chisel-Like)

• This is the first type of Shiv you'll be able to get your hands on, and you will find it on several prisoners in the Aquilla territory. This model of Shiv looks like a chizel.

Shiv (Curved Blade)

• This is a pretty good Shiv - kind of big, compared to some of the other models. It's definitely worth the buy, if you have the UDs to pay for it. This is the Shiv shown on the box of the game, and is likely the best one you'll find.

Shiv (Thick Metal Blade)

• You'll find this Shiv early in the game, but when you get it you'll also have the [Chisel] Shiv and the Thin Shiv to get. This has [the] shortest reach of the three, so pass on it if you see anything better. This shiv looks like a knife with no handle.

Shiv (Thin Metal Blade)

• You'll find this Shiv early in the game, along with the [Chizel] Shiv and the Thick Shiv. It's the longest of them so you may want to choose it. This shiv looks like a knife with no handle.

Scalpel

• You'll find this when you're [in] the Infirmary, so don't pass up on the chance to get it. It's a surgeon's tool, so you can picture what it looks like, but it works great in a fight. This is the second best shiv that you'll be able to find.

Screwdriver

• This is just the average [screwdriver] that you'd expect to see in your tool chest. However, anything can be used as a weapon, if you're Riddick. I'd [recommend] avoiding this one unless you don't have any other shivs.