Several;
S&W 625-2 for revolver
STI Truesite in .40 S&W for Standard.
STI Truesight with 9x40 top end for open
Why, because I have them and at one time or another were considered "the" kit to use.
I wouldn't buy the Truesite again- I'd rather have an Edge or a Truesite with a custom barrel that ditches the expansion chamber (Clarence, if your reading this we should do one).
I had Glock's and an M&P for Production but they were sold but I've really been thinking on the CZ 2012 Shadow...
I've also used a Para P14-45 ltd., it was a good gun, not an STI, but a good gun for the price I paid.
End of the day shoot whatever you have, a G34 will work great.