I think both sides of this argument are right. Microsoft made a mistake by offering no HDD but at least had the sense for it to be upgradeable if the gamer wanted more of the features. Some games are going to require an additional purchase to play them. Some PS3 games require the new EyeToy and that isn't standard in the box. There were PS2 games that required a hard drive, which was an extra purchase until the Slim model came out. Donkey Konga requires some congo drums. A HDD to Microsoft is a peripheral and some systems came standard with them and others didn't. If a developer wants to use the hard drive manually, they just need to put it on the box of the game "HDD Required for Play" or something similar. It's been on many other products.

Only a few 360 buyers were stupid enough to buy those models and most of them knew they would lose out on many features. Those that didn't should honestly get a clue. This isn't only Microsoft that made mistakes like this. Both Nintendo and Sony have and continue to make similar mistakes with their offerings. This doesn't condone Microsoft's mistake, but developers should just do what they need to do to make their game playable. If it cuts a piece of the audience out, that's just a risk they need to assess if it's worth it or not.

you'd think that, but there are people I know that have problems installing any type of software on their computer including games.

Microsoft should consider selling the hard drive addons at cost since it benefits them in the long run (people downloading digital content).

Consoles are becoming more like computers with their high costs and HDD's. PS3 launched with $600 for premium console and XBox 360 launched with $500 for premium console. You can buy a good computer for the cost of those two consoles when they launched.

Based on what sample? I'd prefer to see empirical data and your statements most certainly do not qualify that.

I also doubt the veracity of your claim that the benefits "are well explained" since you're comparing a game from the PS3 to the 360 and you should be well-aware that each system bottlenecks in different places making a direct benefits comparison more or less irrelevant. However, I would guess that developers would see far more benefits than the consumer (sadly easier development does not translate into a more appealing pricetag). Your claims that the 360 fanbase "would be happy about the decision" are specious at best especially considering the already widespread negative PR climate with the 360 and the less than positive PS3 fanbase reaction to installations.

I also find it amusing how you seem to posit that it would be no different than any other peripheral while not addressing the historical fact that peripherals are usually ignored by most all developers anyway.