My first recommendation for veg-centric cookbooks is always Josh McFadden's Six Seasons (eG-friendly Amazon.com link). Some recipes use make-ahead items from the section of "Go-To" pantry recipes in the front of the book so some planning is helpful but the recipes themselves aren't difficult. There's a thread here on cooking from the book so you can take a look and see what you think.
Four books that are not specifically veg-centric but which contain an ample number of veg recipes and were all very popular with the folks in my cookbook group who need to get family dinners on the table quickly are:
Melissa Clark's Dinner: Changing the Game This one is quite a good bang for the cookbook buck as it really has a ton of recipes.
Deb Perelman's Smitten Kitchen Everyday
Julia Turshen's Small Victories:Recipes, Advice + Hundreds of Ideas for Home Cooking Triumphs and her second book may be even better for you, Now & Again: Go-To Recipes, Inspired Menus + Endless Ideas for Reinventing Leftovers
Diana Henry's Simple
Edited to add that while I'm not cooking for a pile-o-kids, I've cooked a lot from those books and really like them, too.
Back on the veg-centric track and an old favorite of mine, Mollie Katzen's Still Life with Menu. In this book, she promotes the idea of doing some small prep tasks ahead so dinners are easy to put together at the end of the day. There are 50 menus and each one has a list of prep work that can be done ahead. There are also quick pasta and stir fry meals, breakfasts and menus for vegetarian Thanksgiving, a vegetarian barbecue and a Seder. There are some weekly menu plans at the end with advance tasks to do each day.
Two books that I haven't seen yet but sound right up your alley are Nigel Slater's Greenfeast: Spring, Summer and Greenfeast: Autumn, Winter, both feature seasonal, quick, easy, vegetarian suppers. The first one hasn't been released yet in the US, the second came out here in September but both were published in the UK last year and have a lot of good reviews.