For GI, I use frosted dome 1-smd leds. Easier on the eyes. Stick to one or two colors related to the general color of the machine. Too much color can be awful.
For inserts, i use 1-smd with clear dome or no dome. Color match those, red for red insert, green for green, etc. Use warm white for orange and yellows.
Check out some youtube videos for examples. TNT does some nice LED jobs.