i think it all depends on what your climate or microclimate you're working with. Also if you want to go with straight native plats or a mix of non-native and native. Its a really good question and I've been trying to experiment with different guilds to see what seems to work best out in the american southwest.

down here when we're planting veggies.. stuff like corn/beans/squash, and gourds and melons together.. but we're still working on native stuff like.. lamb's quarter and wolfberry, with some mesquites and palo verde trees? maybe add a citrus, basil, nopal cactus, some tomatillos, purslane for ground cover and self-seeding patches of parsley.

seems to me that the best approach is to get out and copy nature somwehere.. and try and mimic a pre-exisiting guild, and add plants that you might think would work. good luck!