Titanium screws and black oxide screws are the two you need to look at. There are some trade offs to think of.
Titanium has more tensile strength and bending strength than black oxide steel. This means that Titanium will resist bending longer than the black oxide. This is a good thing. Titanium is weaker than black oxide when it comes to shear strength. This means you are more likely to take the top off of a titanium (shearing it off) than you are with black oxide.
What does all this engineering speak mean to you as the RC modeler? It means that there is no one right answer. If money is an issue, then go with black oxide all around. If you can spring for some Titanium screws, there are some areas on most RCs that are ideally suited for Titanium. I personally run with a mixed bag on my T-Maxx (I have some stainless, black oxide and titanium).
The concern about stripping out the socket (whether philips, hex or slothead) is the next thing to look at. Titanium, black oxide, and stainless is the order of strength from strongest to weakest. Believe it or not, you are better off with a nice set of flathead screws. Yes, you get more contact area on philips or hexhead screws, but you can strip them out more readily than you will kill the slot of a slothead screw.
Bottom line, is that I agree with bloodredmaxx. Of the sets you wanted to look at, the set he pegged is probably the best for the money.
