Linux

PS1="> "

Custom PROMPT variable in my .zshrc. Similar format in .bashrc, but uses PS1 instead.

Prompt shows git branch, italics and custom colors/characters. Shows a hanging arrow on a newline (i know, wasted newlines are blasphemy to some, but I like it).

Renders nicely in my custom compiled suckless terminal using monospace font.

PROMPT='%B%F{blue}[  %B%F{white}$(tput sitm)'%1~'$(tput sgr0)$(tput bold)%B%F{blue}]$(tput sitm)$ %B%F{white}$(tput setaf 5)${vcs_info_msg_0_}%B%F$(tput sgr0)$(tput setaf 4)$(tput bold)
└─>%B%F{white} '

There are two usability tweaks that I would find it hard to live without: (1) red prompt on last-command failure, and (2) highlight what I type, dehighlight output:

Reason for 1 is obvious, 2 is more subtle: it helps my eye scan scrollback and identify what I've typed, which is what I'm scanning for 90% of the time.

Implementations vary, here's how I do it in zsh:

1. PS1='%(?.%K{cyan}%F{white}.%B%K{red}%F{white})XX%b%k%f %(?.%F{cyan}.%F{red})yyy%k%b%F{yellow}%(!.#.$)%f '. Duplication is evil, but AFAIK necessary because the conditional (error check) is %(? and I highlight both parts of my two-part prompt. Suggestions welcome for removing the duplication.
2. zle_highlight=("default:fg=white") (on a Solarized Dark term, where the default fg color is light gray. Adjust to fit your needs).

Zsh and Starship.rs on top with few extra minor things. I like my shell fast and clean.

zsh with prezto and default prompt. I've customized a bit, but the only change I made to the prompt was to replace "..." (three periods) with "…" (ellipsis unicode) since that makes it more compact with a monospace font. I really like the async loading of git status, so I don't have to wait for the command to run before the prompt prints.

I've been using zsh with "oh my zsh". I started using it as it sounded silly and fun compared to bash. Realistically it doesn't really male mich difference. I like the auto complete, but I couldn't say for sure whether it's the shell, oh-my-zsh or what. But I like it.

Fish + OMF.... Work flawlessly

I use bash-it and set it to powerline theme

I'm using guake

I like that it's just the F12 key away then F11 to expand to full window. Supports multiple tabs.

Anyone using guake?

I use budspencer theme on fish. https://github.com/oh-my-fish/oh-my-fish/blob/master/docs/Themes.md#budspencer-theme It looks cool and yellow, which I like. I prints the path on the far right and parent folders are printed only with initial letter, so it doesn't take 2 lines in the shell and it ends up pretty short. It also has git integration and some budspencer exclusive commands to perform some cools actions, I don't care about and I have never used. Also, I like that command errors are displayed as ✔ or ✘ on the next prompt. It also prints the time the last command has been running. I use vi keybidings, so prompt color changes when I change the mode feel cool. I would also like to have the execution time for every command, but I have another theme for that I don't remember the name of on my work machine.