On the RAM issue: It's a very relative and perceived difference in speed when talking about basic use (I'm defining basic use as mail, web, music, word processing, all open at the same time). On my mac, I can have Chrome open with 9 tabs (one of which running flash) while running Aptana Studio with 5 documents open and the XULRunner runner rendering pages for Firefox while talking on Windows Live Messenger and running GIMP with 2 images open in X11. On 4 gigs of ram. I was still able to move around the OS just fine, and still had plenty (About 1 gig) of ram that was Inactive and very little page ins/outs.
Now on my desktop, I push a lot harder workflow sometimes and wish I had 8+ gigs.
Personally, I think a lot of people see the difference from more applications staying in inactive ram, so they get more ram startups than disk startups. This doesn't necessarily mean you needed more ram before, not at all, it means you are keeping more applications "cached" in inactive ram. The general rule of thumb for needing more ram relates to how often you have to page out.
Not to say more ram is a bad thing, some are willing to pay the overhead for a few seconds shaved off subsequent application start times, this is just a personal observation. Like I said, it's relative and perceptual at the level discussed in this thread.
On the topic of this thread:
You said you were writing papers for school on your Mac. By all means, BACK IT UP! It's like having Apple Care, for your data!
I'm curious about the Razer Orichi as well. I want a bluetooth mouse so I can keep one of my USB ports clear (and not having to worry about a cord is nice) and I love Razer products, but I'm not sure how well bluetooth will work overall.