And damn you Nintendo for lowering the price 3 months AFTER I bought my DSi XL. :("
1) One example of this is FPS games. Even though you're restricted to the flat direction of WASD and the mouse, I find it 10x more accurate and easier to aim with than any controller. Though, I may be slightly biased in this regard, when I play Modern Warfare 2 for example, I find it a lot easier to aim on my PC. Even games like Halo (which I have never played on a PC) would probably hold better ground for me on a PC, though the experience of it would be lost because it's clearly meant for consoles.
2) I'm actually with you on this one. If it wasn't for my friend who is very tech savvy, I'd probably be in the dark most of the time. Although, I have taken steps to try and at least learn the vital information needed to know if what I have is good enough. For something like video card specs, if I didn't have my friend, a simple check over at nVIDIA or Newegg might help me figure out where my video card ranks in regards to what is required for a game and how well I figure it might run whatever game I'm after.
3) I don't really know about this one to be honest. I've been using my computer chair for all of my gaming due to the proximity of my computer and TV. Not to mention that I now use my monitor for 360 gaming, so I'm always using the same uncomfortable chair, which I'm pretty sure I'm accustomed to now. To each their own in this regard I guess. :P"
I definitely agree with the beginning sequence of the first Halo. As fun as 2 and 3 were, I don't believe they, or any after them, will ever live up to how epic the first game was.
I wish I could think of other moments, but I'm drawing a blank. :("

