Your best bet is advice from your LHBS. They can talk you through things while giving you visual examples. With that in mind, here's my $0.02:
1. Liquid line length is important to get proper flow from the keg to the glass without adjusting CO2 pressure before every pour. I think you're looking at about 6' of line to get the correct pressure drop, but confirm.
2. Perlicks are awesome. If you don't use the taps every day, the generic ones get stuck on you (both closed AND open, at times). Good call.
3. I don't think shank size is important (adding to joke material). With the right line length, I've gotten as great of flow from a picnic tap as a stainless tap.
4. If you've got room for 5 corneys (and the cash), add the lines/taps for 5. You can always seal off your extra one until you're ready to use it. I started with 3 cornies of capacity and just one tap, so we were opening the kegerator all the time to draw off the picnic taps.
Good luck! Post pics of the finished product in the "Pimp My System" section!