So as you may already know, it's quite possible, and perhaps even easier to RNG in Gen V. It only needs your DS' MAC address and no longer requires your secret ID (previously only legally determinable by catching a wild, non-chained shiny pokemon, figuring out its IVs and using some basic math) and standard non-C-gear RNGing only uses timing precise to the second.
With this in mind, RNGed pokemon might make an even bigger appearance in this generation than the last. What's your opinion on this? Does it devalue the worth of non-RNGed pokemon? Is it perfectly legit? a bad exploit? etcetera.
edit: I just added this FAQ, because people seem to be kinda confused by the whole dealio. Keep in mind that I'm not a programmer or an expert (or even any good!) at RNGing, so if there are any errors/things missing please point them out and I'll fix them ASAP.
Q: What does RNG mean?
A: RNG stands for Random Number Generator. A random number generator (RNG) is something used to create "random" numbers to simulate chance and luck. A die or a deck of cards are both technically RNGs, and so is the bit of programming that determines the pokémon you encounter in-game. An extremely simplified way of thinking of it would be to imagine that every every time you encounter a new pokémon it's like you're rolling a die with millions of sides - each side representing all of the combined attributes (stats, shininess, gender, nature, ability, etcetera) that make up a single pokémon.
Q: Yeah, but what does this have to do with "RNGing" a pokemon?
A: No RNG is perfect, and the numbers generated are often pseudorandom instead of truly "random". Computers often use variables like the time/date, frame, or even fan noise to generate numbers. What this means is that if you know how an RNG works, then you can often figure out a way to make it favour a specific outcome in the same way that you can stack a deck of cards in your favour or drop a die so that it will always land on 6. To keep the analogy going, RNGing means that you can roll the million-sided pokémon die and throw the die in a way that lets you consistently get the side that has the shiny pokémon with perfect stats.
Q: Why do people RNG?
A: RNGing can make it much easier and faster to get a specific pokémon. Instead of hatching thousands of eggs to get a single shiny pokémon with a mostly random nature and IVs, someone who manipulates the RNG can hatch a shiny pokémon, or one with perfect IVs in just a few tries.
Q: Do you need to use a cheating device to RNG?
A: Yes and no. The purpose of RNGing is to allow a player to obtain a flawless, shiny, or otherwise, very specific pokémon without having a cheating device interact directly with their game. Depending on the method, using something like Action Replay while RNGing can even completely throw off the process and make you unable to get the result you want.
During RNGing, the calculations used to find the pokémon you want and determine how to get it on a specific game are very complicated and generally requires users to download programs to their computers that are specially designed to calculate these values. However, these programs will never interact with your game. Whether or not this is considered a cheating device is a controversial issue, but RNGing can technically be done without using any sort of program other than your game itself. Keep in mind that if you're planning on doing all the calculations yourself and without a program, you might want a degree in math first.
In Gen IV, calibrating was easier (in D/P/Pt) because of the pokétch. It was done via the coinflip and happiness checker applications. In Gen V there is no pokétch, so calibrating must be done by catching pokémon and checking their IVs.
Q: So how do I RNG?
A: An in-depth guide would be way more than you could fit in a single question, but there is a step-by-step process here: http://www.smogon.com/forums/showthread.php?t=83057 . It can be pretty confusing and difficult at first, so it's recommended you start off with the standard non-C-gear method.
Q: What is a seed in the context of RNGing?
A: Before the game's RNG generates a random number, you must first provide it with another number so to use to calculate the final "random" number. This first number is called the "seed". The RNG in Black and White is very predictable, and will always spit out the same results when provided with the same seed.
In Gen V the seed is determined by things like the exact time you start up the game, whether or not you start up the C-gear, and also the delay between starting the game and starting your C-gear. By doing all these things at an exact time and following very specific instructions (walking a certain number of steps with a defined number of pokémon in your party, using chatot's chatter, etcetera), you can manipulate the outcome of the game's "dice rolls" and get almost any custom pokémon that you want.
Q: Almost? Which pokémon can't I get then?
A: Although you can have any combination of natures and IVs in this generation, certain pokémon are unable to be generated shiny in your game, even if you hit the seed and frame that would ensure a shiny pokémon. When encountered, these pokémon have will have "checks" on them that will make sure that they will never appear as shiny. The zekrom and reshiram encountered at the end of the game's storyline and at Dragonspiral Tower cannot be encountered as shiny, and neither can Liberty Garden victini. Pokémon from wondercard gifts can also never be shiny, unless the promotion was specifically for a shiny version of that pokémon, in which case you will not be able to get a regular version of that pokémon instead. Finally, pokémon straight from the Dream World in the Entralink Forest are unobtainable as shinies either.