In my case, I use i3 almost all by itself. I use some external services, mostly gnome, like:

- polkit and friends (asks for a password when attempting to run some "admin" task)

- NetworkManager applet (for Wifi / VPN)

- blueman (for Bluetooth)

- udiskie (removable media mounting, with udisks2 behind the scene)

- dunst for notifications

- Rofi for launching apps

I don't use a keyboard layout switcher, but use the US Macintosh layout with level 3 shift for my non-English writing needs (produces dead-keys, like Lvl3+E / E -> é, mapped to the Windows keys).

I don't use a power manager, either. My laptop is happy to give me the same kind of battery life as in Windows with whatever the Arch defaults are.