I personally like the Motorcraft replacement wires. They're grey silicone with black boots, and as Rembrandt said, look just like originals except the don't have cylinder numbers on them.
For the most part, I hate aftermarket wire sets, but one exception is sold by Napa. They're labelled "Wired for Life" and appear to be a very good quality product.
Ford Parts Monkey since 1985
1981 F100 Flareside - Black, 302-4V Roller/AOD
1986 F150 Flareside - Medium Fire Red 302/AOD
1989 F150 Standard Cab 4x4 - Dk Shadow Blue 302/AOD
1993 F350 4x4 Crew Cab - 7.3 IDI/ZF-5
I think it's a sickness...