I have been building and restoring 1911s since I was a kid. Here is a basic list of what I currently think are the best parts. By best I generally mean a combination of the best looking, most tunable/ergonomic, and easiest to fit--
FCG (sear, disco, hammer) - Harrison custom. At this point, just buy the kit. Years ago it was necessary to fit each part, but now frames are so in spec that you will get a better result with their kit. I have worked with some of the best known smiths out there, and they generally use these high spec drop in parts.
Trigger - Harrison custom or Wilson. Harrison is really nice because the overtravel stop is blind and can't wiggle free, but Wilson has adjustable pre travel and can fit in some frames that bind the disco a bit with the Harrison part. I keep both around, and use the Harrison when I can.
Thumb safety - C&S is the best thumb safety for ergos. The finishing is not great on it, and you can't ever seem to get it to be perfect looks wise. The blend on the bottom edge is great, though. Wilson safeties are nearly as nice, but blend best with the Wilson tang cut. Ed Brown safeties are good too.
Beavertail - Wilson and Brown are two different radiuses. I don't like the Wilson radius. With a Brown radius I think the new Stan Chen Beavertail is amazing. Otherwise EGW is really good. If you have a Springfield sometimes you need to use a different radius because of the short tang. Then you are stuck with S&A.
Slide stop - 10-8 or Ed Brown or Harrison
Extractor - Wilson or the newer C&S
Barrel - Kart
Most everything else is fine stock. Any of the above brands are good for any part, if you prefer the way that part looks/feels.