The small ones (4 leds per brick) in the pic above a 1" to give you an idea. I'll probably get the 1" ones in AMBER and put them behind my reverse lights to start....though i think white would be cooler, i think i could use amber with out gettin yelled at by the cops in a appropriate situation. (THICK fog at the coast, pulled over side of road[55mph] to drive my trash cans up and down, huge driveway..; heavy floods around here involve driving in deep deep water) The kid inside of me. If it works out well i'll put some nicer ones in the grill too. I'll see....i'v yet to decide.
http://www.rimindustries.com/able2/leds_by_the_inch.htm <- this web site seems to have ok deals with endless choices.