Let's compile a list of vegetarian/vegan meat replacements.
Generic replacements:
Commercial fake meats:
Similar products (nutrition):
Pardon my rampant vegerianism, but the trick is not to substitue meat at all.
I generally get my nutrition from other sources, without using meat substitutes at all. Unless I really feel like a certain recipe that I used to like back in my meat-eating days.
Use beans, lentils and whole grains for protein. Use nuts, seeds and avocadoes (or any other fatty fruits and vegetables) for B-vitamins. Use beans (again) and leafy greens for iron and calcium.
So, it turns out my answer is a bit Zen. Sorry.
For many dishes mushrooms are a great meat replacement.
Garbanzo beans (chickpeas) make for a delicious veggie burger. Grilled eggplant is also quite lovely.
Quorn based products are quite good meat substitutes. As a hardcore carnivore with a vegetarian partner I was pleasantly surprised at how edible her dishes such as stir fry and bolognese sauce are.
The texture isn't at all strange, sludgy or bouncy and it's the closest thing to a meat texture (probably chicken more like) I've ever had that wasn't actually meat.
Quorn is also high in protein and not much else so if you're after your balance of carbs and fats you need to make sure your other ingredients are supplying them. Also quorn on its own doesn't have much of a taste so you need to season your dish accordingly.
Generic replacements:
Commercial fake meats:
If you go to an Indian store you can find 'Nutrela.' It is dried soy protein. Very popular in India. They have chunks and mince. They are both nice, but I have only tried them Indian style.
Baking shiitake mushrooms lightly tossed in olive oil and salt for an hour on a baking sheet at 350F leads to a quite decent flavor and texture substitute for crispy bacon.
These don't really taste like meat, but burgers made from marinated tofu are nice. If you freeze the tofu first it gets a chewier texture.
Also, fresh paneer (indian cheese) is a nice addition to vegtable dishes, or can be fried on its own: http://en.wikipedia.org/wiki/Paneer
I'm partial to Boca fake chicken. They also have spicy chicken patties that are great (although hard to find in our area).
Fake chicken nuggets are great with hummus and a glass of milk.
I've never had meat so I don't know on a taste basis how they compare but I like the Morningstar foods. I also grew up eating Worthington and Loma Linda brands of fake meat but they are hard to find in most areas. Due to cost and a desire to eat healthier, I don't eat fake meat that much anymore but I still sometimes indulge in Fri-Chik or Morningstar veggie-burgers.
I generally agree with the top-voted answer that fake meats should just be avoided by and large (I feel like much of the perceived ickiness factor that omnis have of veg foods comes from these (often poorly-done) substitutions), but, for personal consumption, when you've got a hankering and anything that even asymptotically approaches the real thing, I suppose they do.
That said, I like using TVP (textured vegetable protein) to make quick taco filling and in spagehtti sauce, chili etc. I get it super-cheap from the bulk section of a local natural food store, and it makes for really quick recipes. e.g. dump a cup of TVP in a tupperware container with some taco seasoning; pour a cup of boiling water over top; mix, put lid on tupperware; wait 5-10 mins. You've got taco filling.
Similarly, one can reconstitute TVP and then mix into spaghetti sauce for a faux bolognease.
These tend to be things I eat a lot of when I'm cooking just for myself and am on a budget (I can get a pound of (dried) TVP for ~$2, which, since TVP is super light, makes a ton!)
Yves has a good line of meat alternative products, including the best vegan hot dogs I've seen anywhere. (I'm not 100% sure that all of their products are vegan, so be sure to check before you buy.)
If you're in the southeast United States, Publix carries vegan tofu crumbles under their Greenwise brand name in the freezer section near the Boca products. I've used them on several occasions to make chili.
My favorite meat replacement product out is Neat. It is 100% vegetarian, soy free, guilt free, and gluten free. Most other replacements I did like the taste or texture, but Neat was different..because I really like it. I have friends who are not vegetarians and love Neat because of how healthy it is and how it tastes just like meat. Check it out! http://eatneat.com
Easy to make and all you need is an egg, water and the mix they provide in there package. Healthy and fast food!
The Beyond Meat burgers that are coming out are pretty close to meat-tasting. If you weren't paying attention, you might miss the difference.
Not sure how many stores carry them, but the A&W fast food chain carries them in Canada as Impossible Burgers.
(note: my comment about sodium content probably still stands with these so I would not make a frequent treat out of them).
Simple Truth has some very good frozen meatless options. They are a natural food brand, not a vegetarian/vegan brand, so a lot of their products are not vegan friendly but their meatless options are good enough I have had to reassert to my relatives (and prove with packaging) that I do not eat meat.
