I think the idea is that if you're running your system at 80-90% on a regular basis, you should look into getting additional RAM
Again, I would have to disagree this point,
if and only if the user is simply doing 1 task and isn't worried about multi-app performance.
If you're multi-tasking, then of course 90% RAM usage is probably not the best thing to have,
unless all your normal multi-tasking, on a regular basis, simply happens to take up 90% RAM. Sure, Windows might be a bit more sluggish because it's got to cache all it's DLLs, etc, but if you're a person that only runs Xvid4PSP while playing TF2 (yours truly!), then having full RAM in that situation isn't inherently "bad", as long as you don't expect the system to be snappy when you open up other large apps.
The only time you're in trouble is when you have misbehaving apps (like someone mentioned), that don't properly allocate and release memory, or work poorly when
forced to use virtual memory (even with lots of RAM)...or too small of a swap file, which is pretty rare.
Also, I think many times people equate unresponsive system or "app stopped reponding" to a crash, which isn't neccesarily the case.
Many times I've seen just "hiccups" or windows say they're not responding...give them an extra few seconds, and often everything reverts to normal (not sure what causes this).
Even TF2 does this now -- I open it up and hit ESC to get past the valve logo, and immediately it looks like I crashed it "Team Fortress 2 (not responding)".
I wait a bit more and it loads just fine.
I know it's a totally tangent point, but since we're diverting way from the thread topic
anyway....
------------------------------------
Really, I think the OP should have titled his thread this way:
"
32 bit will soon no longer be valid"
as I can see games coming out with 64bit .exes just to take break the 2GB app barrier of 32bit Windows
and/or with /3GB switch support, which lowers kernel space to 1GB but gives apps 3GB IIRC.