Well Keith, your edition of Panzer Grenadier is out of antiquity. The current version is 2 generations past it. For direct expansion of what you have, you should look eBay for
Arctic Front and
Edelweiss. Since you said you wanted new stuff, here we go.
- Looking at what's on sale, my first option would be 1940: Fall of France, for a full game. You could follow that up with Road to Dunkirk for a companion game.
- Invasion 1944 would be good too, but I would hesitate over the congested terrain and the counterset is a bit small. You can get Dishonor Before Death to go with it, but you will eventually want to get Elsenborn Ridge to play everything.
- Switching the eastern front, Fire in the Steppe and Armata Romana would be a good combination. All the scenarios for your current game will work and you get some better map art. (Actually the original art was pretty good too.)
- The Kursk games are good, but they don't have any expansions yet.
- In the Pacific, Saipan 1944 and Marianas 1944 are the best combination.
- For something in the Pacific, Kokoda Campaign, but you are always in the jungle.
- Conquest of Ethiopia would be a rather esoteric choice. Good game, unique subject matter, but I think I would wait for Africa Orientale Italiana to go on sale.