i am now exhausted... my MBP 2.6ghz, 4 GB RAM sometimes won't let me quit or force quit out of a program if it crashes. I have to power button off and then start up takes quite a long time... up to 5 - 10 mins sometimes!
i have had it serviced twice and each time the diagnostics have said that the actual computer is fine that it may be a software thing. They did an archive and clean install but i still have the problem.
i am also using my MBP with 2 external eSATA drives and use a lots of music software and plug-ins. i just paid $150 to fix this problem and i still got it!
i use all the same programs on my Mac Pro without these issues!