I second the South Beach Diet pizzas and the Lean Cuisine paninis. I also love the three-cheese rigatoni from Lean Cuisine. I like the Smart Ones veggie lasagna with the spinach and zucchini (sp?).
I love Amy's frozen organic meals! I'm not vegetarian or anything but I eat them because they are tasty. My favorites are the spinach and feta pocket and the bean and cheese burrito. They are around 250 calories I think.
I would recommend the south beach meals b/c they are really high in protein to keep you full! A lot of the healthy choice or lean cuisine meals are really high in refined carbs, so I stay away from them unless I'm really craving mac n cheese or pizza or somethin.
The south beach ones are just lean meat and veggies, so they're a lot healthier than most, in my opinion. The choices are kinda boring though.