Dearest CoCo:
Always a pleasure to read your words, bask in your presence, taste your essence...and I'm sure your cooking is a grounding and ethereal experience, as well! I do not comment as much as I read these days...but some comments, that surely will have already been abundantly answered by others - perhaps these words then can only underscore or nudge against opinions already expressed...
Does the best tasting dish necessarily demand the most expensive products from the toniest market? [I think I know the answer to this one]
Never! Good quality, especially veggies, trumps cost - does it look fresh and healthy? It probably is! Same goes for such staples as stock, pasta, and the like. Good brands sell to everyone. Sometimes "organic" as a label is meaningful (Swanson boxed broths, for example), often it is not (it's just a marketing label like "lite"). But quality is not assured by high price. The best guide is to try a product, and see if you like it. With standarized labels, you can check out things like calories and sodium to compare products.
Sometimes great cuisine is a matter of little tricks of the trade: avoid a buillion cube and instead look for a packaged stock, or perhaps a concentrated demi-glace (which might not be at the corner market - demi-glace is a super-concentrated stock, it looks expensive, but lasts for many a dish). Grilling or broiling veggies is a great alternative. Quick stir fries are easy and maintain nutrients and flavors.
What naturally growing flora do you gather and eat, say, like dock, miner's lettuce, etc.
In the desert, we're pretty limited to what we grow on our own - rosemary, basil, a few other herbs. We don't have a lot of experience gathering nature's own bounty, so I'm afraid I can't comment much. Between us and our families, we've cultivated potatoes, squash, corn, lettuce, cabbage, tomatoes, carrots, radishes, turnips, apricots, peaches, plums, apples - my folks' current tomatoes are planted in half-barrels on the rear deck.
Is fresh everything always the key to a tasty meal?
Well, for those things that you want fresh, usually. Meats can be frozen, as can many veggies (steam corn ears then freeze for a winter full of deliciousness) and fruits (just pop your blueberries and strawberries in the freezer), and of course canning and pickling brings its own flavors to the table.
Fresh herbs versus dried herbs is usually just a matter of quantity - dried herbs and seasonings are concentrated, so a recipe that calls for one needs to be adjusted for the other.
Some things are just different rather than better: fresh pasta versus dried pasta can be rather similar, but most of us are more familier with dried pasta and perhaps more comfortable with that.
If fresh isn't available, what's preferable: canned or frozen?
Frozen, at least in the case of veggies like corn. Canned often has been processed more, has more additives. Canned fruits often have added sugar - which may be a sweet temptation, but may also distract from the flavor of the fruit and therefore the dish. If you have a little freezer room, buy when fresh and freeze for later use. This of course doesn't work for fresh leafy things like lettuce, but does work for things like prepared spinach, corn (it can be cut from the cob), carrots...
Does it really matter that my Extra Virgin Olive Oil is from Tunisia or Spain?
Only when you taste the difference and want something else. Spanish versus Italian, for example, is a completely different flavor palette. Once you decide on that basic dichotomy, you will want to choose between Extra Virgin and Not - and, rather than a rule, you will also want to go by your taste. Extra Virgin is the first pressing of the olive, and will have a much more organic flavor than subsequent pressings. Is Extra Virgin better? Only if you enjoy that flavor! There's nothing wrong with liking a lighter falvored oilive oil - and you may want a stronger flavored oil for bread dipping as opposed to cooking.
If the oil tastes to you like it is overpowering a dish, use a less expensive pressing.
There are so many Websites that speak to olive oils that I won't even try to go any further!
How do you dress up mac and cheese? [all right, somebody gave me these here boxes of gluey elbows]
Here's a couple choices: one of the best standard mac and cheese recipes is Alton Brown's, here:
http://www.foodnetwork.com/recipes/alton-brown/baked-macaroni-and-cheese-recipe/index.html
...or, try something a little more adventurous with Penne al Forno - sadly I will have to get back with you on that recipe, but it's an oven-baked pasta in a cheese sauce (asiago preferred) with onion and breadcrumbs on top. Traditionally it's made with penne pasta, but really any can be used.
Any good recipes a la cheap?
I enjoy a simple stir fry made with sprouts, celery, some napa cabbage and soy sauce, a little meat can be added if it's at hand. Bread (with a hard crust, preferably homebaked!) and some sharp cheddar, rounded off with an apple, is a favorite of mine. I love tacos: some hamburger, toss in some hot New Mexico (or milder California) chili powder, garlic salt, and pepper, fry that up in a pan and put it in some tortillas...