hooboy..... here goes nothing....
Curious, have you asked him, or will consider asking him if what he really wants is a Wii and not the other 2 systems? If you get a reply, don't settle for just "yes" or "no". Get some reasons and arguments on why he'd want a Wii and not the other 2 consoles. Just "yes" or "no" sounds like he didn't really look into it or is just going by peer pressure. Ask him if he also looked into the other 2 console systems as well. If it sounds like he knows what he really wants, then go with it. After all, whether if its movies, hobbies, or food, no one will know his video game interests better than himself. However, in the end, there's always the chance he'll get bored with a Wii or realize hes made the wrong choice. AFAIK, it's something children go through. They don't ALWAYS know what they want, and frankly, even adults go through this as well, although I'd imagine it's less so for them. At least this'll be a good lesson for him in high-end consumerism. He's learning more what to expect in terms of the odds-and-ends of a product, what he should look out for next time he researches a video game console, as well as what to look out for before making decisions about relatively expensive purchases. Even though you're buying it for him, hes still getting a lesson there in budgets, as it still counts against his budget of personal items you're willing to buy him in a given time. When he gets older, he can get anything he wants, but now he'll have to spend his own $$, and will be better about that since he'll have first hand experience in prioritizing his wants.
.
As for the 3 consoles, I don't own any of them, but I have played all 3 of them. There's no clear winner here. Just 3 groups polarized in 3 different directions, like with many types of products like cell phone service providers and mp3 players. Some go in either or multiple directions, while others refuse to go certain ways. Of the latter, some may find their "blacklisted consoles" are not so bad afterall, but yet others are confirmed that it's just not for them. I grew up on Nintendo from 1986 up to 2001. Later on, I added PC games to the mix. From 2001 to present, I still play vid games from various systems and sources. It do have a thing for Nin, but I will make my in depth coverage to be unbiased. In the end, if you have the $$, you get more than one or all 3 of the. If not, you need to make a choice of which one you want (which is your sons case)
Wii
Good thing with the Wii is you could probably get in on the action as well. The motion sensing is a blast to play. Playing sports games (like Wii Sports and Wii Play) on the wiimote is truly fun. I've also played a game called Monkey Ball: Banana Blitz. It's a collection of mini-games, from the typical real life activities like throwing darts, archery, to the not so familiar like a game where you direct a falling ball to collect as many items as possible by tilting the remote to control platforms. Like a custom, very souped up Plinko game from The Price Is Right if you will. These games that lend themselves to this sort of real life realism work out wonderfully when using the motion controlled wiimote as an interface.
Then there are other games like Zelda Twilight Princess (played through a dungeon at a friend's house) and Super Mario Galaxy (of which I beat several levels at an EB Games). Those games are definately fun and well done, but personally, I would've preferred if they toned down the wiimote interaction. However, I could live with having to shake or swing the wiimote even tho it feels "less necessary" in this case. Using the wiimote to point at the screen to shoot at things does fell natural at least. These kinds of games on the Wii may not have as much appeal to you as above, but I believe you may also get into these as well
It has the reputation of being a "kiddie system". That's part true. All the Nintendo franchises like Mario, Legend Of Zelda, Metroid, Donkey Kong, Star Fox, etc. may attract kids, but the fact that adults are really into them doesnt make the Wii exclusively a kiddie system. Just think of all the adults who enjoy watching movies like Finding Nemo or Harry Potter and enjoy them despite being targeted towards an children audience. On the other hand, Nintendo does have more than a few games of mini-games in its collections, some even like party games. However, I hear Nin's doing a much better job of getting some games that are also better geared towards adults. For example, in this list...
http://www.destructoid.com/top-10-most-promising-wii-games-of-2007-28493.phtml
about half of them are more adult oriented.
Online experience here has some games with multiplayer, but less so than the other 3 systems. Theres also social interaction, checking stuff like news and weather, and the Virtual Console. The VC has a wide library of previous Nintendo games like form n64, Super Nintendo, and NES to download and play. Also have some non Nintendo consoles available like Turbo Graphics 16 and the Sega Genesis. All available at moderate prices. Good alternative to scouring pawn shops and ebay for older games, and having to connect multiple consoles to the TV when one console does most of it.
PlayStation 3
prices have gone down, but it's still the most expensive of the 3. On the plus side, it comes with bluray player, so you're into HD movies, that'll be a plus. As far as game selection goes, PS3 games are more similar to 360 games than Wii games. More games available for online multiplayer gaming. No fee required for that either. While these games are more oriented for adults its certainly possible some of it wont appeal to adults. The games tend to be more graphically realistic, and contain more adult material like sexual content, blood, gore, and adult themes like betrayal, murder, and blackmail. IMHO, it really isnt that much worse than many of todays movies that hes allowed to see at his age.
Xbox 360
cheaper system overall, but if you add the HD-DVD add-on, it comes about even with a PS3. Games like Gears Of War are truly unique with its own atmosphere you wont find anywhere else. Online play is better organized, but theres a $50/yr fee for that. Games here are roughly on par with a PS3. In graphical quality as well as all the adult oriented stuff.
PS3 and 360 notes
-If you don't have a HDTV or won't have one by the time you make a PS3 purchase, it's OK. Just realize while the picture quality for games and HDTV will still be good, it won't be the best.
-While the game types for these 2 systems are similar what sets them a part are the titles and franchises available. That would be left to your son to decide what appeals to him.
-these also have some games for younger audiences as well
OTHER NOTES
-One thing to keep in mind is Wiis are rather difficult to find this holiday season, so you'll want to plan ahead and/or pay something reasonable above the $250 MSRP.
Thats about it. I promised myself I would keep this as concise as possible so Ill stop it at here. I would stick with the Wii unless youre convinced hes QUITE sure he would want something else in the near future. Barring any personal preferences, any of the 3 consoles would really work out fine. If he makes the wrong choice, thats something he needs to deal with, as do we all.
Good luck and happy holidays!