Some of my favorites:
England - Lon >> EC, Lvp >> Yor, Edi >> Nth. If you can negotiate a supported convoy into Belgium and still afford to attack France, do it. If you can't, move your fleet to Belgium and take Norway. In gunboat, support yourself into Belgium and let France either block Brest or vacate the MAO; either way, he can't hurt you in S02. You get an army on the mainland and avoid the mess known as Scandinavia for the time being. It's always there later but the mainland will close up quick, especially if one of them attacks you first.
France - Bre >> MAO, Par >> Bur, Mar S Par >> Bur; MAO >> Por, Bur >> Bel, Mar >> Pie. Negotiate this shit with Italy and rip Germany to shreds. Get English support into Belgium and then build a fleet in Brest anyway if you have two. Two birds one stone. If you only have one, build an army and then take Spain whenever you feel like it. Nobody else is going to take it so you might as well save it for when you need it. The I/F is the most underrated alliance in Diplomacy.
Italy - Ven >> Pie, Rom >> Apu, Nap >> Ion; convoy to Tunis, support France back to Marseilles. Fuck with France, keep them on edge. Take Marseilles in the spring, and if you can't, make sure France has to cover it in the fall. Work with Austria, tear Turkey up, and then pick your next target. Nobody can touch you once Turkey goes down.
Also Italy - Ven >> Tyr, Rom >> Ven, Nap >> Ion; option 1: Ven >> Tri, Tyr S Ven >> Tri, Ion >> Tun; option 2: Tyr >> Boh, Ven >> Tri, Ion >> Tun. Option 1 is an attack on Austria, option 2 is negotiated. Typically, option 2 will have been negotiated from the start, but it's rare that you'll find an Austrian player who will go with it. Another option is to move to Tyrolia alone, follow to Bohemia, and convoy to Tunis, leaving open a lepanto and an indirect attack on Russia simultaneously. With a friendly France, option 2 and 3 are both damn near guaranteed successful.
Austria - Tri >> Alb, Bud >> Ser, Vie >> Bud; Alb >> Ion (Italy moves to Aegean), Bud >> Ser, Ser >> Gre (or Bud >> Rum with Ser support). Takes a lot of negotiation with Italy but absolutely devastates Turkey, particularly if he bounces the Black Sea in S01. It opens the door for a move into the later stages of a key without an Italian army having to move through, though a fun way to play it is to have an Italian army keying as a mutual trust arrangement with Austria in the Ionian and Italy in Serbia.