I don't have Royal Road to Card Magic, but I have Modern Coin Magic. Some of my favorite effects from that book would be Gadabout Coins, Three and Three, Four Coins through table, and all the coin through hand effects.
i agree completely
as far as royal road to card magic: i have found nearly every thing in that book useful, and use alot of it on a regular basis.if i had to pick one, it would be the classic force, just because the ways you can produse cards are limitless. some of my favorites are,
card in wallet
card in shoe
card in spectators backpack(if at school)
your imagination is the limit