I'm not going to list all my favorites because I'm too lazy to hop onto my laptop and because the majority of them have been covered so here's two that I haven't seen referenced yet.

[hider=Batman][img]https://static0.cbrimages.com/wp-content/uploads/2018/08/Batman-Damned-Jim-Lee-cover.jpg?lossless=1&q=40&w=728&h=929&fit=crop[/img]

For Batman, I have always loved Lee Bermejo's take on the suit in Joker and Batman: Noel. The rendering of it by Jim Lee however made me fall in love with it all over again.[/hider]

[hider=Dick Grayson][img]https://pre00.deviantart.net/b833/th/pre/i/2015/142/b/b/young_justice__robin_by_philbourassa-d3zdz80.jpg[/img]

I think Young Justice did a better job of modernizing the Robin suit than the comics have so for Dick Grayson as Robin this is definitely my pick.

[img]https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQjxyKqqwyXvP1-p-5FeMi1JS9ptkfJ1bktDmR5ms0kS_4b94lK[/img]

This was hard because I love the classic Black and Blue, the DCAU and the Rebirth costumes. But honestly once you recolor the second Nightwing suit from the New52 to blue instead of red it is pretty tight in my opinion. Plus it retains the finger stripes which are by far the most important aspect of the suit :P. 

[img]https://vignette.wikia.nocookie.net/marvel_dc/images/c/c6/Dick_Grayson_Earth_2_0002.jpg/revision/latest?cb=20150528122229[/img]

I love this Earth-2 Dickbats because it so obviously homages the Disco Nightwing suit while still being obviously Batman. It does things differently too from a lot of other Batsuits and most importantly it's one of the few times where it's not Dick standing in for Bruce but rather a version of Dick who is free to carve his own identity beneath the cowl. [/hider]