Allen keys, torque wrench, torx drivers, chain tool, BB tool, cassette lockring tool, headset press, cable cutters.
I'd strongly recommend doing it. I have just built up an S-Works Enduro and enjoyed every minute. Racing Ralph (Rob)kindly lent me a few of the tools and a workstand, although I didn't need a headset press, as it came pre-installed.
It took me a day, but I had a few breaks to do other things and plenty of drinks/smokes, so I reckon half a day if you get stuck in. There was a little bit of trial and error, but everything works fantastically well and the feeling of satisfaction is great. It's certainly running sweeter and for longer than any other bike I've had built up by some shop monkey.