Most used INT range in Fallout 1/2 characters?

[Coyote]

But if you have Sniper, Luck 10, and Fast Shot, then that is even cooler, right? More attacks without targetted shots. And all those additional attacks will be critical hits.

Yep, Sniper along with high luck/agility, Bonus Rate of Fire, Fast Shot, and Better Criticals makes for a killer end-game build. Some points in Action Boy don't hurt, either, especially since you tend to get more out of them if you're using Fast Shot and Bonus Rate of Fire. Of course, you have to get to that point first, but it's not like the NWNs where a lot of the best epic builds suck throughout the lower levels; most of these attributes/traits/perks are pretty useful throughout the game if you build this sort of critical hit-oriented character (although I like having the option of aimed shots, so I'd probably use Mutate! to get Fast Shot, replacing something like Finesse, if I was going down this route).

If you're asking specifically about Fast Shot: without Fast Shot it's still quite powerful. You can cause instant kills by shooting people in the eyes, which helps a lot on the high-HP, high-DR enemies you encounter towards the end of the game (at least in FO2; I don't think I've ever gotten a character in FO to a high enough level to pick up Sniper/Slayer). I'd be hard-pressed to say which is better, and it probably depends on what weapons you're using.