Benefits of Companion Planting...

As I look out my window like Tennyson's Mariana in the Moated Grange, I sigh and say, "My garden in dreary, spring cometh not, my garden looks mostly dead".. and then I go back to by books with lots of colorful pictures. Lucy says pretty at all of the flowers, well if you know what she's saying, that's what it is. It probably sounds like "p" "t" and "y" all slurred together, but that's how it is. This leads me to thinking again of companion planting. How? you ask. Well I'll tell you...I don't know.
I'm sure your next question would be, "What is companion planting?" (unless you are among the elite who know all about this, and then you can humor us or skip to the next paragraph) First I'll tell you what it isn't. It is not planting with your significant other to strengthen the bonds of you relationship or keep the pangs of loneliness far away. Likewise it is not planting two plant in the same hole so that they don't get lonely.
It is planting beneficial plants next to each other so that they both thrive in a symbiotic relationship. (another score for watching Jurassic Park)
There is a lot of really heady knowledge about the who, what, when, where, and hows; but I'm going to skip to the fun part - what to plant next to each other for stellar results. I sifted the world wide web and a few different books compiling a list on my yellow pad. You too can do this if you have the desire or time, and fill in all the parts I missed. I also only posted things that I found in multiple areas believing that may lead to more sure results. As I have never done any companion planting, this is all here say until after this year.

• Nasturtiums repel beetles and especially aphids. They can be planted randomly through out your garden or next to any especially sensitive plant. 
• Marigolds repel most insects, but must be the scented varieties. The con of this is that they also attract spider mites and slugs, so be ware. Also, don't plant these next to beans. 
• Garlic is a good aphid repellent for the roses. Imagine the bouquet for your nose walking through a garlic/rose garden! This also is assists in the growth and flavor of beets.
• Basil helps tomato growth and flavor. It also repels thrips, flies, and mosquitoes. However, avoid planting it near rue or sage. 
• Rosemary, Dill, and Sage all repel most pests with their distinct aroma. 
• Broccoli grows well with celery, onions, and potatoes.
• Chives improve carrots and tomatoes, also blessing and keeping aphids far from them. 
• Coriander/Cilantro. This was a teaser for a bit until I learned (try not to laugh out loud) that Coriander is the dried seeds and Cilantro are the leaves. This is good for repelling insects. Also, the leaves can be made into a tea that is good spider mite spray. 
• Bay Leaves are good for repelling lady bugs. You may think that this is bad, and I'd agree in the garden setting, however, if you have had lots, and lots, and lots of them living and dying in your windows, you'll be glad to know that next time just spread the bay leaves like confetti and they should leave. Pun intended.
• Dill helps out Lettuce.
• Mints. Be careful here. These will help your Brassaca Family (broccoli, radishes, cabbage and the like). However, they are very invasive. So either plan on dealing harshly with them or just plant them elsewhere and mulch the mint leaves scattering their tattered remains amidst the bassica fields. Then the get that advantage with out being overgrown. 
• Parsley will increase the smell or odor or nose bouquet of the your roses.
• Plant radishes with your squash plants. They repel squash bugs and also attract the slugs. This will keep the slugs from eating your squash plants, and the radishes won't suffer from the slugs. 
• Odd tip...Boiled rhubarb leaves make a good black spot spray for roses. Don't eat them though. Bad stuff.

Avoid:
Planting Asparagus next to Onions, Garlic, or Potatoes.
Planting Carrots with Dill or Parsnips

Like I said earlier, there are way more than these few, but these I found to be most helpful to my plans. There were things about nematodes and other insects I've only heard about, but have never done any serious battling against. These I didn't pay much attention to...yet. I like the idea, because I won't have to use any chemicals if all goes well and shouldn't see too much crop loss either.
A really crazy idea, I don't know if I'm going to try it or not, is to plant Corn, beans and pumpkins in the same area. The Corn provides poles for the beans, and the pumpkin smother weeds growing around the corn. Theoretically plausible... however...