Three things that killed the PS3 for me:
1. The seriously poor decision to turn their back on PS2 owners by mucking around with the Backwards compatibility to the point that it's a completely abandoned mess. I'm not even sure they are working on correcting the emulation of certain games, because quite frankly Sony's position is that they want you to buy and play PS3 games, not sit around reliving your formative years with PS2 classic games you love. This is even worse with some of the less popular titles (Star Ocean: Til the end of time, Suikoden V). Mostly it was the way they chose to handle this and comments by it's management in regards to this that felt extremely condescending that really tweaked me and left me with a bad taste in my mouth.
My purchase of a 60 GB PS3 however resolved this for me, but only when I came across one at an extremely good price. No way I'd have paid full price for a new 80 gb.
2. The inability to change the stupid frakkin white text on the main dashboard menu. Seriously, the fact that after countless updates there is STILL NO OPTION to change this infuriates me enough to kick puppies. What POSSIBLE reason can Sony have for not allowing this function? It completely negates the ability to set my own wallpaper background from my own pictures because I have to select the most absolute dark color I can BECAUSE THAT WHITE TEXT CANNOT BE CHANGED!
I know I know, some people might find this a trivial gripe, but in an age where PC's are customizable to your particular taste, and where people enjoy personalizing their technology, this is as inexcusable as making a FPS with no online multiplayer or online CO-Op.
It's touted as the most technologically superior console on the market bar none, and yet changing something so bloody simple as menu text is like asking them to release the secrets of the Freemasons. Ridiculous.
3. Nickel and dime accessory scam.
Ok it's bad enough that all the consoles think it's ok these days to ship with one friggin controller and then charge you extravagant amounts of money for a second. But Sony takes this to a new extreme by first refusing to kick in an 8 dollar HDMI cable so you can get the most out of their much touted graphics capability and BLU-Ray player. However, I suppose this is a minor issue, but then it turns out to transfer my old PS1 and PS2 saves (you know, for the dozens of RPG worlds still hanging in the balance because I never got around to defeating the great "evil" Mage/Empire/Force/Meteor/God that threatens the universe) I need to buy yet ANOTHER ridiculously overpriced accessory, the Memory Card Adapter! Mind you, this is a ONE TIME USE item that You use, transfer your friggin saves to the hard drive, and then wham! You can toss it in the trash because the chances of you EVER needing it again are nil to none. To make things worse, it's not even reasonably priced at like $5, the damn thing can set you back a full $20. Thats the price of a friggin PS2 GAME! Thanks Sony for managing to exclude such a nifty, yet cheap, tool in that whopping $400 product you want people to buy.
And thus sums up what I feel is the reason why PS3's arent selling like gangbusters IMO. Sony's bone-headed almost intentionally mean business tactics that piss all over their fan-base in the quest to part you from just one more of your precious hard earned dollars.
I didnt even bother with Home and Playstation Online's flaws because it only matters really if you are an online game fan.
Xbox's have their issues too, but I at least I feel like Microsoft is TRYING to make me a customer as opposed to Sony who seems to be acting like I owe THEM some sort of favor for the privilege of "owning" their system.