If you are already planning a lasagne, I'd have an Italian inspired salad on the side: lettuce, tomato, fresh basil, balsamic glaze, red onions, olives etc or a Greek salad (not Italian I know!
Plus garlic/herb bread
For my own dinner party/gatherings, it depends on the season and who is coming. A luncheon on a hot, summers day might be quiche, various salads, new potatoes etc
An evening meal in the winter- rib of beef, yorkshires, cauli cheese, carrots, peas, cabbage/bacon
If the in-laws are coming, I often do prawn cocktail as an entree.
If our 6"7' friend is coming, I do more meaty options. Slow cooked pork ribs in a sticky hoisin sauce, peri peri chicken, corn on the cob or whatever is in season.