To answer a few of your questions:
1) As Pink mentioned, your system is plenty capable. In general I'd think about some more memory (RAM), but you should be okay for audio.
2) General system crashes are really probably not MC's fault. I'd first try running the newest version of MC (which is .266 at this time) and see if that happens to fix it. When it (probably) doesn't, then you want to investigate the other software and hardware on your system. First, make sure you are Spyware free (run both Ad-Aware and Spybot scans -- make sure they're updated) and Virus free. Spyware can really be the cause of lots of problems. Once you're satisfied you've got no nasties, you might want to do some hardware tests, just to rule out bad RAM or an overheating system.
Check this thread for more info.
3) Dumb luck? We'll cross that bridge after we eliminate the problems above.
4) Because MC11 is still (for the moment) officially pre-release software, the "Check for Updates" function does not always show the latest available version. The JRiver folks are rediculously hard working, and actually put out a new build of MC
almost every weekday. The version you see at the top of the forum list (the "sticky" one) is the most recent build. This will change once MC version 11 is officially released (probably very soon). Of course, then they will start working on version 12 (and releasing builds soon enough I suspect).
5) Again, check for non-MC problems first. Once they've been eliminated, then do a search on this forum. I don't know of any specific problems that are common (though others might).
6) Actually, when I got to this one I realized that it could be the cause of some of your slowness! Go to Tools --> Options --> File Location. Set base path to wherever you'd like your music saved (eg. "C:\music\") and then set:
Directory Rule:
[Artist]\[Album]
Filename Rule:
[Track #] - [Name]
That should do what you want. The way it works is that the Directory rule creates the folders. Replacing the stuff in the [] with the proper information. The "\" separates it into subdirectories.
The filename rule works the same way. Anything not in a [] is put verbatim in the filenames as is. So, if you put:
Directory Rule:
tearduct ! - [Artist]\[Album]
Filename Rule:
[Track #] - cheesenoodle - [Name]
And then ripped "The Gorge" you'd get your songs in a folder called:
"tearduct ! - Dave Matthew's Band" and then inside a folder called "The Gorge".
The songs themselves would be called:
1 - cheesenoodle - Pantala Naga Pampa/Rapunzel
2 - cheesenoodle - Song That Jane Likes
3 - cheesenoodle - Fool to Think
...and so on.