[QUOTE=PSX]I just finally bought my first VC game a couple weeks ago, and I immediately had this same thought once I realized that there was no way to transfer the games between systems. It really bothers me too. But some people might prefer it. Here's the good part and the bad part:
GOOD
If you sell your Wii console on eBay, Craigslist, etc., having the VC games will increase its value. Let's say I own a Xbox 360 and I want to sell it. And let's say I don't care about all my Xbox Live Arcade games anymore... well, I can't get rid of them unless I give the buyer my Xbox Live account too. So if you never plan to use those XLA games again, they either basically "disappear" when you sell your console (stuck to an unused account) or you give up your XLA account to the buyer (which might contain personal info). But with the Wii, you can get some value back for those VC games if you sell the console. So if you spent $300 on some really good VC games, maybe someone would give you like an extra $150 for your Wii. Can't really do that if you sell your PS3.
BAD
Exactly what happened to Paul. Basically, you can't buy $300 in VC games today, and tomorrow you're Wii could smash to the ground.. and all your VC games are gone. On the Xbox 360 and PS3, your games are preserved when your console stops working. Also, as a counter to the above point, you could sell your console without losing your XLA and PSN games, if you wanted to keep them.
I personally prefer the Microsoft and Sony model, but there is at least some merit for certain people in the Nintendo model.
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Actually I'm afraid this is wrong, you can sell your PS3 or 360 and the downloadable games with them without handing over your account at all.
360:
When you buy a game on XBLA it's locked to the console you buy it on. You can still play the game on another console if you are online however with the profile that bought it. You can also, once per year, transfer licenses to your new machine to play them offline if you want. So if you bought Sonic 4 on XBLA and sold your machine on, as long as you didn't migrate the license the person who bought your machine can happily play Sonic 4.
PS3:
This is actually handled the same way as the Wii. When you buy a game you acquire a certain number of licenses, for some games like Wipeout and Warhawk it's one, for others 3 or 5. Each new machine you download the game to uses up another license. They may have a way for you to migrate now but if so it's a new thing that they didn't use to have. This system actually led to widespread piracy where one person would buy a game then loan their tag round so their friends could get it.
So on both systems you can sell them with the games still on without handing over your tag.