We are just transitioning to a vegetarian diet (I am leaning more vegan, but currently pregnant and haven't gotten rid of greek yogurt yet), so i have been trying to build a recipe base recently, trying lots of new things. Some current winners:
Creamy Avocado pasta: http://www.flourishingfoodie.com/2012/03/creamy-avocado-pasta.html
Tuscan Chickpea soup: http://www.myrecipes.com/recipe/tuscan-chickpea-soup-10000000231724/
Falafel (I made a tahini sauce and baked them as per some of the reviews) - http://allrecipes.com/Recipe/Seans-Falafel-and-Cucumber-Sauce/Detail.aspx
Red Lentil Coconut soup: http://www.scalingbackblog.com/savory-bites/16117996741/
Pad Thai - http://browniesfordinner.com/2010/05/11/easy-pad-thai/
Pho (left out the chicken, added tofu for me) - http://www.eatliverun.com/asian-chicken-noodle-soup/
Tacos with beans instead of meat
Homemade veggie pizza
My two boys (5 and 3 yrs) eat just about anything, and haven't noticed the disappearance of meat. When they were less than a year, we gave them a lot of beans and lentils. With our first, we pureed everything to start, but with our second, we just gave him whatever we were eating, smashing a bit with a fork if necessary. If it was soup, we just scooped out the veggies/noodles onto a plate for him. He is much less picky about textures as a result. Until DS2 was 2yrs, if we were having a salad, I would just steam him some carrots or broccoli instead.
So I second the ideas about lentils, beans. Also quinoa and other grains. You can also get brown rice and quinoa pasta for fingerfoods if you want to avoid wheat.
Hummus dip - you can do lots of various dips actually...adding different beans, veggies, etc. (black beans, artichokes, edamame - if you are ok with whole soybeans)
And eventually, nut/seed butters (almond, sunflower) spread on tortillas/crackers
If you eat dairy/eggs, it opens up a bunch of options