For years I have used Adobe Premier Elements v. 3.0 to edit my videos because it worked OK and probably more importantly came in a package with Adobe Photoshop Elements (which is a very good tool, except for the organizer which I don't like). But I have a PC with a 64-bit operating system and a quad core CPU for which this older software is not optimized -- the old 3.0 was running painfully slowly even on my new computer. So I downloaded a trial edition of Premier Elements 7 and was horrified at how buggy and unstable it was, without adding any real functionality that I wanted over the old 3.0 edition. So I then downloaded the brand new v 8.0 and found it if anything even worse. In retrospect, I could have seen this in the reviews for both products on Amazon.
I have a general rule of thumb that one bad version generation happens, but two in a row means it is time for a change (the exception to this being Quickbooks, which has had about 4 versions in a row where each is worse than the last, but there is really not a good alternative for me right now).
For video editing, I eventually landed on the oddly named Sony Vegas Movie Studio, v9.0. I am extremely happy. It works a lot like Elements used to but is rock solid stable. I have been working with a 90-minute HD video for 2 days straight without a reboot and it has had no problems and is fast and has all the functionality I could want. Not for casual applications probably, but I really like it. I don't usually write posts like this, but this piece of software almost never makes it into the magazine reviews or comparisons at sites like PC Magazine or CNET. Not sure why, but its an excellent program. Thanks to the Amazon community, whose reviews again helped me make a good decision.
Postscript: I have never been wildly impressed with Adobe programming and their most recent iteration of Photoshop Elements really worries me as the organizer seems to be badly bugged. Their programs have always been pigs -- the only way they could get a tolerable load time for Elements was to break the program into four parts and start up with a menu that lets one choose one part or the other. I know they did this to fight the classic Adobe load time problem (used to have it in spades with Acrobat reader) but I think they have broken something in the process. You know Adobe programs are a pig when I get impatient for them to load from the new Intel SSD, which generally serves up programs lightening fast.